Command tests (#922)

* WIP command tests

* Finish marking todo tests

* update

* update

* Windows cd test ignoring

crates/nu-command/src/core_commands/tutor.rs

@@ -426,7 +426,7 @@ fn display(help: &str, engine_state: &EngineState, stack: &mut Stack, span: Span
                 if let Ok(output) = decl.run(
                     engine_state,
                     stack,
-                    &Call::new(),
+                    &Call::new(span),
                     Value::String {
                         val: item.to_string(),
                         span: Span { start: 0, end: 0 },

crates/nu-command/src/filesystem/open.rs

@@ -142,7 +142,7 @@ impl Command for Open {
                     Some(converter_id) => engine_state.get_decl(converter_id).run(
                         engine_state,
                         stack,
-                        &Call::new(),
+                        &Call::new(call_span),
                         output,
                     ),
                     None => Ok(output),

crates/nu-command/src/filesystem/save.rs

@@ -71,7 +71,7 @@ impl Command for Save {
                     let output = engine_state.get_decl(converter_id).run(
                         engine_state,
                         stack,
-                        &Call::new(),
+                        &Call::new(span),
                         input,
                     )?;
 

crates/nu-command/src/filters/columns.rs

@@ -82,6 +82,10 @@ fn getcol(
                 .map(move |x| Value::String { val: x, span })
                 .into_pipeline_data(engine_state.ctrlc.clone()))
         }
+        PipelineData::Value(Value::Record { cols, .. }, ..) => Ok(cols
+            .into_iter()
+            .map(move |x| Value::String { val: x, span })
+            .into_pipeline_data(engine_state.ctrlc.clone())),
         PipelineData::Value(..) | PipelineData::RawStream(..) => {
             let cols = vec![];
             let vals = vec![];

crates/nu-command/src/filters/lines.rs

@@ -30,7 +30,7 @@ impl Command for Lines {
         input: PipelineData,
     ) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
         let head = call.head;
-        let skip_empty = call.has_flag("skip-emtpy");
+        let skip_empty = call.has_flag("skip-empty");
         match input {
             #[allow(clippy::needless_collect)]
             // Collect is needed because the string may not live long enough for
@@ -39,13 +39,21 @@ impl Command for Lines {
             PipelineData::Value(Value::String { val, span }, ..) => {
                 let split_char = if val.contains("\r\n") { "\r\n" } else { "\n" };
 
-                let lines = val
+                let mut lines = val
                     .split(split_char)
                     .map(|s| s.to_string())
                     .collect::<Vec<String>>();
 
+                // if the last one is empty, remove it, as it was just
+                // a newline at the end of the input we got
+                if let Some(last) = lines.last() {
+                    if last.is_empty() {
+                        lines.pop();
+                    }
+                }
+
                 let iter = lines.into_iter().filter_map(move |s| {
-                    if skip_empty && s.is_empty() {
+                    if skip_empty && s.trim().is_empty() {
                         None
                     } else {
                         Some(Value::string(s, span))
@@ -65,21 +73,30 @@ impl Command for Lines {
                                 split_char = "\r\n";
                             }
 
-                            let inner = val
+                            let mut lines = val
                                 .split(split_char)
                                 .filter_map(|s| {
-                                    if skip_empty && s.is_empty() {
+                                    if skip_empty && s.trim().is_empty() {
                                         None
                                     } else {
-                                        Some(Value::String {
+                                        Some(s.to_string())
-                                            val: s.into(),
-                                            span,
-                                        })
                                     }
                                 })
-                                .collect::<Vec<Value>>();
+                                .collect::<Vec<_>>();
 
-                            Some(inner)
+                            // if the last one is empty, remove it, as it was just
+                            // a newline at the end of the input we got
+                            if let Some(last) = lines.last() {
+                                if last.is_empty() {
+                                    lines.pop();
+                                }
+                            }
+
+                            Some(
+                                lines
+                                    .into_iter()
+                                    .map(move |x| Value::String { val: x, span }),
+                            )
                         } else {
                             None
                         }
@@ -102,13 +119,21 @@ impl Command for Lines {
                 let split_char = if s.contains("\r\n") { "\r\n" } else { "\n" };
 
                 #[allow(clippy::needless_collect)]
-                let lines = s
+                let mut lines = s
                     .split(split_char)
                     .map(|s| s.to_string())
                     .collect::<Vec<String>>();
 
+                // if the last one is empty, remove it, as it was just
+                // a newline at the end of the input we got
+                if let Some(last) = lines.last() {
+                    if last.is_empty() {
+                        lines.pop();
+                    }
+                }
+
                 let iter = lines.into_iter().filter_map(move |s| {
-                    if skip_empty && s.is_empty() {
+                    if skip_empty && s.trim().is_empty() {
                         None
                     } else {
                         Some(Value::string(s, head))

crates/nu-command/src/formats/from/ics.rs

@@ -94,6 +94,13 @@ END:VCALENDAR' | from ics",
 
 fn from_ics(input: PipelineData, head: Span, config: &Config) -> Result<PipelineData, ShellError> {
     let input_string = input.collect_string("", config)?;
+
+    let input_string = input_string
+        .lines()
+        .map(|x| x.trim().to_string())
+        .collect::<Vec<_>>()
+        .join("\n");
+
     let input_bytes = input_string.as_bytes();
     let buf_reader = BufReader::new(input_bytes);
     let parser = ical::IcalParser::new(buf_reader);
@@ -103,9 +110,9 @@ fn from_ics(input: PipelineData, head: Span, config: &Config) -> Result<Pipeline
     for calendar in parser {
         match calendar {
             Ok(c) => output.push(calendar_to_value(c, head)),
-            Err(_) => output.push(Value::Error {
+            Err(e) => output.push(Value::Error {
                 error: ShellError::UnsupportedInput(
-                    "input cannot be parsed as .ics".to_string(),
+                    format!("input cannot be parsed as .ics ({})", e),
                     head,
                 ),
             }),

crates/nu-command/src/formats/from/vcf.rs

@@ -125,14 +125,24 @@ END:VCARD' | from vcf",
 
 fn from_vcf(input: PipelineData, head: Span, config: &Config) -> Result<PipelineData, ShellError> {
     let input_string = input.collect_string("", config)?;
+
+    let input_string = input_string
+        .lines()
+        .map(|x| x.trim().to_string())
+        .collect::<Vec<_>>()
+        .join("\n");
+
     let input_bytes = input_string.as_bytes();
     let cursor = std::io::Cursor::new(input_bytes);
     let parser = ical::VcardParser::new(cursor);
 
     let iter = parser.map(move |contact| match contact {
         Ok(c) => contact_to_value(c, head),
-        Err(_) => Value::Error {
+        Err(e) => Value::Error {
-            error: ShellError::UnsupportedInput("input cannot be parsed as .vcf".to_string(), head),
+            error: ShellError::UnsupportedInput(
+                format!("input cannot be parsed as .vcf ({})", e),
+                head,
+            ),
         },
     });
 

crates/nu-command/src/network/fetch.rs

@@ -265,7 +265,7 @@ fn helper(
                         Some(converter_id) => engine_state.get_decl(converter_id).run(
                             engine_state,
                             stack,
-                            &Call::new(),
+                            &Call::new(span),
                             output,
                         ),
                         None => Ok(output),

crates/nu-command/src/strings/str_/trim/command.rs

@@ -2,14 +2,14 @@ use nu_engine::CallExt;
 use nu_protocol::{
     ast::{Call, CellPath},
     engine::{Command, EngineState, Stack},
-    Example, PipelineData, ShellError, Signature, Span, SyntaxShape, Value,
+    Example, PipelineData, ShellError, Signature, Span, Spanned, SyntaxShape, Value,
 };
 
 #[derive(Clone)]
 pub struct SubCommand;
 
 struct Arguments {
-    character: Option<Value>,
+    character: Option<Spanned<String>>,
     column_paths: Vec<CellPath>,
 }
 
@@ -143,7 +143,16 @@ where
         input,
     );
     let to_trim = match options.character.as_ref() {
-        Some(v) => v.as_string()?.chars().next(),
+        Some(v) => {
+            if v.item.chars().count() > 1 {
+                return Err(ShellError::SpannedLabeledError(
+                    "Trim only works with single character".into(),
+                    "needs single character".into(),
+                    v.span,
+                ));
+            }
+            v.item.chars().next()
+        }
         None => None,
     };
 

crates/nu-command/src/system/run_external.rs

@@ -220,7 +220,7 @@ impl ExternalCommand {
                                 &crate::Table,
                                 &engine_state,
                                 &mut stack,
-                                &Call::new(),
+                                &Call::new(head),
                                 input,
                             );
 

crates/nu-command/tests/commands/all.rs

@@ -0,0 +1,57 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn checks_all_rows_are_true() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+                echo  [ "Andrés", "Andrés", "Andrés" ] 
+                | all? $it == "Andrés"
+        "#
+    ));
+
+    assert_eq!(actual.out, "true");
+}
+
+#[test]
+fn checks_all_rows_are_false_with_param() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+                [1, 2, 3, 4] | all? { |a| $a >= 5 }
+        "#
+    ));
+
+    assert_eq!(actual.out, "false");
+}
+
+#[test]
+fn checks_all_rows_are_true_with_param() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+                [1, 2, 3, 4] | all? { |a| $a < 5 }
+        "#
+    ));
+
+    assert_eq!(actual.out, "true");
+}
+
+#[test]
+fn checks_all_columns_of_a_table_is_true() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+                echo [
+                        [  first_name, last_name,   rusty_at, likes  ];
+                        [      Andrés,  Robalino, 10/11/2013,   1    ]
+                        [    Jonathan,    Turner, 10/12/2013,   1    ]
+                        [      Darren, Schroeder, 10/11/2013,   1    ]
+                        [      Yehuda,      Katz, 10/11/2013,   1    ]
+                ]
+                | all? likes > 0
+        "#
+    ));
+
+    assert_eq!(actual.out, "true");
+}

crates/nu-command/tests/commands/any.rs

@@ -0,0 +1,33 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn checks_any_row_is_true() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+                echo  [ "Ecuador", "USA", "New Zealand" ] 
+                | any? $it == "New Zealand"
+        "#
+    ));
+
+    assert_eq!(actual.out, "true");
+}
+
+#[test]
+fn checks_any_column_of_a_table_is_true() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+                echo [
+                        [  first_name, last_name,   rusty_at, likes  ];
+                        [      Andrés,  Robalino, 10/11/2013,   1    ]
+                        [    Jonathan,    Turner, 10/12/2013,   1    ]
+                        [      Darren, Schroeder, 10/11/2013,   1    ]
+                        [      Yehuda,      Katz, 10/11/2013,   1    ]
+                ]
+                | any? rusty_at == 10/12/2013
+        "#
+    ));
+
+    assert_eq!(actual.out, "true");
+}

crates/nu-command/tests/commands/append.rs

@@ -0,0 +1,15 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn adds_a_row_to_the_end() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+                echo  [ "Andrés N. Robalino", "Jonathan Turner", "Yehuda Katz" ] 
+                | append "pollo loco"
+                | nth 3
+        "#
+    ));
+
+    assert_eq!(actual.out, "pollo loco");
+}

crates/nu-command/tests/commands/cal.rs

@@ -0,0 +1,87 @@
+use nu_test_support::{nu, pipeline};
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn cal_full_year() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        cal -y --full-year 2010 | first | to json
+        "#
+    ));
+
+    let first_week_2010_json = r#"{"year":2010,"sunday":null,"monday":null,"tuesday":null,"wednesday":null,"thursday":null,"friday":1,"saturday":2}"#;
+
+    assert_eq!(actual.out, first_week_2010_json);
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn cal_february_2020_leap_year() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        cal -ym --full-year 2020 --month-names | where month == "february" | to json
+        "#
+    ));
+
+    let cal_february_json = r#"[{"year":2020,"month":"february","sunday":null,"monday":null,"tuesday":null,"wednesday":null,"thursday":null,"friday":null,"saturday":1},{"year":2020,"month":"february","sunday":2,"monday":3,"tuesday":4,"wednesday":5,"thursday":6,"friday":7,"saturday":8},{"year":2020,"month":"february","sunday":9,"monday":10,"tuesday":11,"wednesday":12,"thursday":13,"friday":14,"saturday":15},{"year":2020,"month":"february","sunday":16,"monday":17,"tuesday":18,"wednesday":19,"thursday":20,"friday":21,"saturday":22},{"year":2020,"month":"february","sunday":23,"monday":24,"tuesday":25,"wednesday":26,"thursday":27,"friday":28,"saturday":29}]"#;
+
+    assert_eq!(actual.out, cal_february_json);
+}
+
+#[test]
+fn cal_friday_the_thirteenths_in_2015() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        cal --full-year 2015 | default friday 0 | where friday == 13 | length
+        "#
+    ));
+
+    assert!(actual.out.contains('3'));
+}
+
+#[test]
+fn cal_rows_in_2020() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        cal --full-year 2020 | length
+        "#
+    ));
+
+    assert!(actual.out.contains("62"));
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn cal_week_day_start_monday() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        cal --full-year 2020 -m --month-names --week-start monday | where month == january | to json
+        "#
+    ));
+
+    let cal_january_json = r#"[{"month":"january","monday":null,"tuesday":null,"wednesday":1,"thursday":2,"friday":3,"saturday":4,"sunday":5},{"month":"january","monday":6,"tuesday":7,"wednesday":8,"thursday":9,"friday":10,"saturday":11,"sunday":12},{"month":"january","monday":13,"tuesday":14,"wednesday":15,"thursday":16,"friday":17,"saturday":18,"sunday":19},{"month":"january","monday":20,"tuesday":21,"wednesday":22,"thursday":23,"friday":24,"saturday":25,"sunday":26},{"month":"january","monday":27,"tuesday":28,"wednesday":29,"thursday":30,"friday":31,"saturday":null,"sunday":null}]"#;
+
+    assert_eq!(actual.out, cal_january_json);
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn cal_sees_pipeline_year() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        cal --full-year 1020 | get monday | first 3 | to json
+        "#
+    ));
+
+    assert_eq!(actual.out, "[3,10,17]");
+}

crates/nu-command/tests/commands/cd.rs

@@ -0,0 +1,277 @@
+use nu_test_support::fs::Stub::EmptyFile;
+use nu_test_support::nu;
+use nu_test_support::playground::Playground;
+use std::path::PathBuf;
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn filesystem_change_from_current_directory_using_relative_path() {
+    Playground::setup("cd_test_1", |dirs, _| {
+        let actual = nu!(
+            cwd: dirs.root(),
+            r#"
+                cd cd_test_1
+                echo (pwd)
+            "#
+        );
+
+        assert_eq!(PathBuf::from(actual.out), *dirs.test());
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn filesystem_change_from_current_directory_using_absolute_path() {
+    Playground::setup("cd_test_2", |dirs, _| {
+        let actual = nu!(
+            cwd: dirs.test(),
+            r#"
+                cd "{}"
+                echo (pwd)
+            "#,
+            dirs.formats()
+        );
+
+        assert_eq!(PathBuf::from(actual.out), dirs.formats());
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn filesystem_switch_back_to_previous_working_directory() {
+    Playground::setup("cd_test_3", |dirs, sandbox| {
+        sandbox.mkdir("odin");
+
+        let actual = nu!(
+            cwd: dirs.test().join("odin"),
+            r#"
+                cd {}
+                cd -
+                echo (pwd)
+            "#,
+            dirs.test()
+        );
+
+        assert_eq!(PathBuf::from(actual.out), dirs.test().join("odin"));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn filesytem_change_from_current_directory_using_relative_path_and_dash() {
+    Playground::setup("cd_test_4", |dirs, sandbox| {
+        sandbox.within("odin").mkdir("-");
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            r#"
+                cd odin/-
+                echo (pwd)
+            "#
+        );
+
+        assert_eq!(
+            PathBuf::from(actual.out),
+            dirs.test().join("odin").join("-")
+        );
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn filesystem_change_current_directory_to_parent_directory() {
+    Playground::setup("cd_test_5", |dirs, _| {
+        let actual = nu!(
+            cwd: dirs.test(),
+            r#"
+                cd ..
+                echo (pwd)
+            "#
+        );
+
+        assert_eq!(PathBuf::from(actual.out), *dirs.root());
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn filesystem_change_current_directory_to_two_parents_up_using_multiple_dots() {
+    Playground::setup("cd_test_6", |dirs, sandbox| {
+        sandbox.within("foo").mkdir("bar");
+
+        let actual = nu!(
+            cwd: dirs.test().join("foo/bar"),
+            r#"
+                cd ...
+                echo (pwd)
+            "#
+        );
+
+        assert_eq!(PathBuf::from(actual.out), *dirs.test());
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn filesystem_change_current_directory_to_parent_directory_after_delete_cwd() {
+    Playground::setup("cd_test_7", |dirs, sandbox| {
+        sandbox.within("foo").mkdir("bar");
+
+        let actual = nu!(
+            cwd: dirs.test().join("foo/bar"),
+            r#"
+                rm {}/foo/bar
+                echo ","
+                cd ..
+                echo (pwd)
+            "#,
+            dirs.test()
+        );
+
+        let actual = actual.out.split(',').nth(1).unwrap();
+
+        assert_eq!(PathBuf::from(actual), *dirs.test().join("foo"));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn filesystem_change_to_home_directory() {
+    Playground::setup("cd_test_8", |dirs, _| {
+        let actual = nu!(
+            cwd: dirs.test(),
+            r#"
+                cd ~
+                echo (pwd)
+            "#
+        );
+
+        assert_eq!(Some(PathBuf::from(actual.out)), dirs_next::home_dir());
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn filesystem_change_to_a_directory_containing_spaces() {
+    Playground::setup("cd_test_9", |dirs, sandbox| {
+        sandbox.mkdir("robalino turner katz");
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            r#"
+                cd "robalino turner katz"
+                echo (pwd)
+            "#
+        );
+
+        assert_eq!(
+            PathBuf::from(actual.out),
+            dirs.test().join("robalino turner katz")
+        );
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn filesystem_not_a_directory() {
+    Playground::setup("cd_test_10", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("ferris_did_it.txt")]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "cd ferris_did_it.txt"
+        );
+
+        assert!(
+            actual.err.contains("ferris_did_it.txt"),
+            "actual={:?}",
+            actual.err
+        );
+        assert!(
+            actual.err.contains("is not a directory"),
+            "actual={:?}",
+            actual.err
+        );
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn filesystem_directory_not_found() {
+    Playground::setup("cd_test_11", |dirs, _| {
+        let actual = nu!(
+            cwd: dirs.test(),
+            "cd dir_that_does_not_exist"
+
+        );
+
+        assert!(
+            actual.err.contains("dir_that_does_not_exist"),
+            "actual={:?}",
+            actual.err
+        );
+        assert!(
+            actual.err.contains("directory not found"),
+            "actual={:?}",
+            actual.err
+        );
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn filesystem_change_directory_to_symlink_relative() {
+    Playground::setup("cd_test_12", |dirs, sandbox| {
+        sandbox.mkdir("foo");
+        sandbox.mkdir("boo");
+        sandbox.symlink("foo", "foo_link");
+
+        let actual = nu!(
+            cwd: dirs.test().join("boo"),
+            r#"
+                cd ../foo_link
+                echo (pwd)
+            "#
+        );
+
+        assert_eq!(PathBuf::from(actual.out), dirs.test().join("foo"));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[cfg(target_os = "windows")]
+#[test]
+fn test_change_windows_drive() {
+    Playground::setup("cd_test_20", |dirs, sandbox| {
+        sandbox.mkdir("test_folder");
+
+        let _actual = nu!(
+            cwd: dirs.test(),
+            r#"
+                subst Z: test_folder
+                Z:
+                echo "some text" | save test_file.txt
+                cd ~
+                subst Z: /d
+            "#
+        );
+        assert!(dirs
+            .test()
+            .join("test_folder")
+            .join("test_file.txt")
+            .exists());
+    })
+}

crates/nu-command/tests/commands/compact.rs

@@ -0,0 +1,50 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn discards_rows_where_given_column_is_empty() {
+    Playground::setup("compact_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "los_tres_amigos.json",
+            r#"
+                {
+                    "amigos": [
+                        {"name":   "Yehuda", "rusty_luck": 1},
+                        {"name": "Jonathan", "rusty_luck": 1},
+                        {"name":   "Andres", "rusty_luck": 1},
+                        {"name":"GorbyPuff"}
+                    ]
+                }
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open los_tres_amigos.json
+                | get amigos
+                | compact rusty_luck
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "3");
+    });
+}
+#[test]
+fn discards_empty_rows_by_default() {
+    Playground::setup("compact_test_2", |dirs, _| {
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                echo "[1,2,3,14,null]"
+                | from json
+                | compact
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "4");
+    });
+}

crates/nu-command/tests/commands/cp.rs

@@ -0,0 +1,241 @@
+use nu_test_support::fs::{files_exist_at, AbsoluteFile, Stub::EmptyFile};
+use nu_test_support::nu;
+use nu_test_support::playground::Playground;
+use std::path::Path;
+
+#[test]
+fn copies_a_file() {
+    Playground::setup("cp_test_1", |dirs, _| {
+        nu!(
+            cwd: dirs.root(),
+            "cp \"{}\" cp_test_1/sample.ini",
+            dirs.formats().join("sample.ini")
+        );
+
+        assert!(dirs.test().join("sample.ini").exists());
+    });
+}
+
+#[test]
+fn copies_the_file_inside_directory_if_path_to_copy_is_directory() {
+    Playground::setup("cp_test_2", |dirs, _| {
+        let expected_file = AbsoluteFile::new(dirs.test().join("sample.ini"));
+
+        nu!(
+            cwd: dirs.formats(),
+            "cp ../formats/sample.ini {}",
+            expected_file.dir()
+        );
+
+        assert!(dirs.test().join("sample.ini").exists());
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn error_if_attempting_to_copy_a_directory_to_another_directory() {
+    Playground::setup("cp_test_3", |dirs, _| {
+        let actual = nu!(
+            cwd: dirs.formats(),
+            "cp ../formats {}", dirs.test()
+        );
+
+        assert!(actual.err.contains("../formats"));
+        assert!(actual.err.contains("resolves to a directory (not copied)"));
+    });
+}
+
+#[test]
+fn copies_the_directory_inside_directory_if_path_to_copy_is_directory_and_with_recursive_flag() {
+    Playground::setup("cp_test_4", |dirs, sandbox| {
+        sandbox
+            .within("originals")
+            .with_files(vec![
+                EmptyFile("yehuda.txt"),
+                EmptyFile("jonathan.txt"),
+                EmptyFile("andres.txt"),
+            ])
+            .mkdir("expected");
+
+        let expected_dir = dirs.test().join("expected").join("originals");
+
+        nu!(
+            cwd: dirs.test(),
+            "cp originals expected -r"
+        );
+
+        assert!(expected_dir.exists());
+        assert!(files_exist_at(
+            vec![
+                Path::new("yehuda.txt"),
+                Path::new("jonathan.txt"),
+                Path::new("andres.txt")
+            ],
+            expected_dir
+        ));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn deep_copies_with_recursive_flag() {
+    Playground::setup("cp_test_5", |dirs, sandbox| {
+        sandbox
+            .within("originals")
+            .with_files(vec![EmptyFile("manifest.txt")])
+            .within("originals/contributors")
+            .with_files(vec![
+                EmptyFile("yehuda.txt"),
+                EmptyFile("jonathan.txt"),
+                EmptyFile("andres.txt"),
+            ])
+            .within("originals/contributors/jonathan")
+            .with_files(vec![EmptyFile("errors.txt"), EmptyFile("multishells.txt")])
+            .within("originals/contributors/andres")
+            .with_files(vec![EmptyFile("coverage.txt"), EmptyFile("commands.txt")])
+            .within("originals/contributors/yehuda")
+            .with_files(vec![EmptyFile("defer-evaluation.txt")])
+            .mkdir("expected");
+
+        let expected_dir = dirs.test().join("expected").join("originals");
+
+        let jonathans_expected_copied_dir = expected_dir.join("contributors").join("jonathan");
+        let andres_expected_copied_dir = expected_dir.join("contributors").join("andres");
+        let yehudas_expected_copied_dir = expected_dir.join("contributors").join("yehuda");
+
+        nu!(
+            cwd: dirs.test(),
+            "cp originals expected --recursive"
+        );
+
+        assert!(expected_dir.exists());
+        assert!(files_exist_at(
+            vec![Path::new("errors.txt"), Path::new("multishells.txt")],
+            jonathans_expected_copied_dir
+        ));
+        assert!(files_exist_at(
+            vec![Path::new("coverage.txt"), Path::new("commands.txt")],
+            andres_expected_copied_dir
+        ));
+        assert!(files_exist_at(
+            vec![Path::new("defer-evaluation.txt")],
+            yehudas_expected_copied_dir
+        ));
+    })
+}
+
+#[test]
+fn copies_using_path_with_wildcard() {
+    Playground::setup("cp_test_6", |dirs, _| {
+        nu!(
+            cwd: dirs.formats(),
+            "cp ../formats/* {}", dirs.test()
+        );
+
+        assert!(files_exist_at(
+            vec![
+                Path::new("caco3_plastics.csv"),
+                Path::new("cargo_sample.toml"),
+                Path::new("jonathan.xml"),
+                Path::new("sample.ini"),
+                Path::new("sgml_description.json"),
+                Path::new("utf16.ini"),
+            ],
+            dirs.test()
+        ));
+    })
+}
+
+#[test]
+fn copies_using_a_glob() {
+    Playground::setup("cp_test_7", |dirs, _| {
+        nu!(
+            cwd: dirs.formats(),
+            "cp * {}", dirs.test()
+        );
+
+        assert!(files_exist_at(
+            vec![
+                Path::new("caco3_plastics.csv"),
+                Path::new("cargo_sample.toml"),
+                Path::new("jonathan.xml"),
+                Path::new("sample.ini"),
+                Path::new("sgml_description.json"),
+                Path::new("utf16.ini"),
+            ],
+            dirs.test()
+        ));
+    });
+}
+
+#[test]
+fn copies_same_file_twice() {
+    Playground::setup("cp_test_8", |dirs, _| {
+        nu!(
+            cwd: dirs.root(),
+            "cp \"{}\" cp_test_8/sample.ini",
+            dirs.formats().join("sample.ini")
+        );
+
+        nu!(
+            cwd: dirs.root(),
+            "cp \"{}\" cp_test_8/sample.ini",
+            dirs.formats().join("sample.ini")
+        );
+
+        assert!(dirs.test().join("sample.ini").exists());
+    });
+}
+
+#[test]
+fn copy_files_using_glob_two_parents_up_using_multiple_dots() {
+    Playground::setup("cp_test_9", |dirs, sandbox| {
+        sandbox.within("foo").within("bar").with_files(vec![
+            EmptyFile("jonathan.json"),
+            EmptyFile("andres.xml"),
+            EmptyFile("yehuda.yaml"),
+            EmptyFile("kevin.txt"),
+            EmptyFile("many_more.ppl"),
+        ]);
+
+        nu!(
+            cwd: dirs.test().join("foo/bar"),
+            r#"
+                cp * ...
+            "#
+        );
+
+        assert!(files_exist_at(
+            vec![
+                "yehuda.yaml",
+                "jonathan.json",
+                "andres.xml",
+                "kevin.txt",
+                "many_more.ppl",
+            ],
+            dirs.test()
+        ));
+    })
+}
+
+#[test]
+fn copy_file_and_dir_from_two_parents_up_using_multiple_dots_to_current_dir_recursive() {
+    Playground::setup("cp_test_10", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("hello_there")]);
+        sandbox.mkdir("hello_again");
+        sandbox.within("foo").mkdir("bar");
+
+        nu!(
+            cwd: dirs.test().join("foo/bar"),
+            r#"
+                cp -r .../hello* .
+            "#
+        );
+
+        let expected = dirs.test().join("foo/bar");
+
+        assert!(files_exist_at(vec!["hello_there", "hello_again"], expected));
+    })
+}

crates/nu-command/tests/commands/def.rs

@@ -0,0 +1,22 @@
+use nu_test_support::nu;
+use nu_test_support::playground::Playground;
+use std::fs;
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn def_with_comment() {
+    Playground::setup("def_with_comment", |dirs, _| {
+        let data = r#"
+#My echo
+def e [arg] {echo $arg}
+            "#;
+        fs::write(dirs.root().join("def_test"), data).expect("Unable to write file");
+        let actual = nu!(
+            cwd: dirs.root(),
+            "source def_test; help e | to json"
+        );
+
+        assert!(actual.out.contains("My echo\\n\\n"));
+    });
+}

crates/nu-command/tests/commands/default.rs

@@ -0,0 +1,35 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn adds_row_data_if_column_missing() {
+    Playground::setup("default_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "los_tres_amigos.json",
+            r#"
+                {
+                    "amigos": [
+                        {"name":   "Yehuda"},
+                        {"name": "Jonathan", "rusty_luck": 0},
+                        {"name":   "Andres", "rusty_luck": 0},
+                        {"name":"GorbyPuff"}
+                    ]
+                }
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open los_tres_amigos.json
+                | get amigos
+                | default rusty_luck 1
+                | where rusty_luck == 1
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "2");
+    });
+}

crates/nu-command/tests/commands/drop.rs

@@ -0,0 +1,72 @@
+use nu_test_support::{nu, pipeline};
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn columns() {
+    let actual = nu!(
+        cwd: ".", pipeline(r#"
+            echo [
+              [arepas, color];
+
+              [3,  white]
+              [8, yellow]
+              [4,  white]
+            ]
+            | drop column
+            | get
+            | length
+        "#)
+    );
+
+    assert_eq!(actual.out, "1");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn more_columns_than_table_has() {
+    let actual = nu!(
+        cwd: ".", pipeline(r#"
+            echo [
+              [arepas, color];
+
+              [3,  white]
+              [8, yellow]
+              [4,  white]
+            ]
+            | drop column 3
+            | get
+            | empty?
+        "#)
+    );
+
+    assert_eq!(actual.out, "true");
+}
+
+#[test]
+fn rows() {
+    let actual = nu!(
+        cwd: ".", pipeline(r#"
+            echo [
+              [arepas];
+
+              [3]
+              [8]
+              [4]
+            ]
+            | drop 2
+            | get arepas
+            | math sum
+        "#)
+    );
+
+    assert_eq!(actual.out, "3");
+}
+
+#[test]
+fn more_rows_than_table_has() {
+    let actual = nu!(cwd: ".", "date | drop 50 | length");
+
+    assert_eq!(actual.out, "0");
+}

crates/nu-command/tests/commands/each.rs

@@ -0,0 +1,83 @@
+use nu_test_support::{nu, pipeline};
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn each_works_separately() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo [1 2 3] | each { echo $it 10 | math sum } | to json
+        "#
+    ));
+
+    assert_eq!(actual.out, "[11,12,13]");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn each_group_works() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo [1 2 3 4 5 6] | each group 3 { $it } | to json
+        "#
+    ));
+
+    assert_eq!(actual.out, "[[1,2,3],[4,5,6]]");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn each_window() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo [1 2 3 4] | each window 3 { $it } | to json
+        "#
+    ));
+
+    assert_eq!(actual.out, "[[1,2,3],[2,3,4]]");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn each_window_stride() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo [1 2 3 4 5 6] | each window 3 -s 2 { echo $it } | to json
+        "#
+    ));
+
+    assert_eq!(actual.out, "[[1,2,3],[3,4,5]]");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn each_no_args_in_block() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo [[foo bar]; [a b] [c d] [e f]] | each { to json } | nth 1 | str collect
+        "#
+    ));
+
+    assert_eq!(actual.out, r#"{"foo":"c","bar":"d"}"#);
+}
+
+#[test]
+fn each_implicit_it_in_block() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo [[foo bar]; [a b] [c d] [e f]] | each { nu --testbin cococo $it.foo }
+        "#
+    ));
+
+    assert_eq!(actual.out, "ace");
+}

crates/nu-command/tests/commands/echo.rs

@@ -0,0 +1,61 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn echo_range_is_lazy() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo 1..10000000000 | first 3 | to json --raw
+        "#
+    ));
+
+    assert_eq!(actual.out, "[1,2,3]");
+}
+
+#[test]
+fn echo_range_handles_inclusive() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo 1..3 | each { $it } | to json --raw
+        "#
+    ));
+
+    assert_eq!(actual.out, "[1,2,3]");
+}
+
+#[test]
+fn echo_range_handles_exclusive() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo 1..<3 | each { $it } | to json --raw
+        "#
+    ));
+
+    assert_eq!(actual.out, "[1,2]");
+}
+
+#[test]
+fn echo_range_handles_inclusive_down() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo 3..1 | each { $it } | to json --raw
+        "#
+    ));
+
+    assert_eq!(actual.out, "[3,2,1]");
+}
+
+#[test]
+fn echo_range_handles_exclusive_down() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        echo 3..<1 | each { $it } | to json --raw
+        "#
+    ));
+
+    assert_eq!(actual.out, "[3,2]");
+}

crates/nu-command/tests/commands/empty.rs

@@ -0,0 +1,94 @@
+use nu_test_support::{nu, pipeline};
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn reports_emptiness() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+            echo [[are_empty];
+                     [([[check]; [[]]      ])]
+                     [([[check]; [""]      ])]
+                     [([[check]; [(wrap)] ])]
+            ]
+            | get are_empty
+            | empty? check
+            | where check
+            | length
+        "#
+    ));
+
+    assert_eq!(actual.out, "3");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn sets_block_run_value_for_an_empty_column() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+            echo [
+                     [  first_name, last_name,   rusty_at, likes  ];
+                     [      Andrés,  Robalino, 10/11/2013,   1    ]
+                     [    Jonathan,    Turner, 10/12/2013,   1    ]
+                     [       Jason,     Gedge, 10/11/2013,   1    ]
+                     [      Yehuda,      Katz, 10/11/2013,  ''    ]
+            ]
+            | empty? likes -b { 1 }
+            | get likes
+            | math sum
+        "#
+    ));
+
+    assert_eq!(actual.out, "4");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn sets_block_run_value_for_many_empty_columns() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+            echo [
+                     [  boost   check   ];
+                     [     1,    []     ]
+                     [     1,    ""     ]
+                     [     1,  (wrap)  ]
+            ]
+            | empty? boost check -b { 1 }
+            | get boost check
+            | math sum
+        "#
+    ));
+
+    assert_eq!(actual.out, "6");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn passing_a_block_will_set_contents_on_empty_cells_and_leave_non_empty_ones_untouched() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+            echo [
+                     [      NAME, LVL,   HP ];
+                     [    Andrés,  30, 3000 ]
+                     [  Alistair,  29, 2900 ]
+                     [    Arepas,  "",   "" ]
+                     [     Jorge,  30, 3000 ]
+            ]
+            | empty? LVL -b { 9 }
+            | empty? HP -b {
+                $it.LVL * 1000
+              }
+            | math sum
+            | get HP
+        "#
+    ));
+
+    assert_eq!(actual.out, "17900");
+}

crates/nu-command/tests/commands/enter.rs

@@ -0,0 +1,73 @@
+use nu_test_support::fs::{files_exist_at, Stub::EmptyFile};
+use nu_test_support::nu;
+use nu_test_support::playground::Playground;
+use std::path::Path;
+
+#[test]
+fn knows_the_filesystems_entered() {
+    Playground::setup("enter_test_1", |dirs, sandbox| {
+        sandbox
+            .within("red_pill")
+            .with_files(vec![
+                EmptyFile("andres.nu"),
+                EmptyFile("jonathan.nu"),
+                EmptyFile("yehuda.nu"),
+            ])
+            .within("blue_pill")
+            .with_files(vec![
+                EmptyFile("bash.nxt"),
+                EmptyFile("korn.nxt"),
+                EmptyFile("powedsh.nxt"),
+            ])
+            .mkdir("expected");
+
+        let red_pill_dir = dirs.test().join("red_pill");
+        let blue_pill_dir = dirs.test().join("blue_pill");
+        let expected = dirs.test().join("expected");
+        let expected_recycled = expected.join("recycled");
+
+        nu!(
+            cwd: dirs.test(),
+            r#"
+                enter expected
+                mkdir recycled
+                enter ../red_pill
+                mv jonathan.nu ../expected
+                enter ../blue_pill
+                cp *.nxt ../expected/recycled
+                p
+                p
+                mv ../red_pill/yehuda.nu .
+                n
+                mv andres.nu ../expected/andres.nu
+                exit
+                cd ..
+                rm red_pill --recursive
+                exit
+                n
+                rm blue_pill --recursive
+                exit
+            "#
+        );
+
+        assert!(!red_pill_dir.exists());
+        assert!(files_exist_at(
+            vec![
+                Path::new("andres.nu"),
+                Path::new("jonathan.nu"),
+                Path::new("yehuda.nu"),
+            ],
+            expected
+        ));
+
+        assert!(!blue_pill_dir.exists());
+        assert!(files_exist_at(
+            vec![
+                Path::new("bash.nxt"),
+                Path::new("korn.nxt"),
+                Path::new("powedsh.nxt"),
+            ],
+            expected_recycled
+        ));
+    })
+}

crates/nu-command/tests/commands/every.rs

@@ -0,0 +1,211 @@
+use nu_test_support::fs::Stub::EmptyFile;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn gets_all_rows_by_every_zero() {
+    Playground::setup("every_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+            EmptyFile("los.txt"),
+            EmptyFile("tres.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | get name
+                | every 0
+                | to json --raw
+            "#
+        ));
+
+        assert_eq!(
+            actual.out,
+            r#"["amigos.txt","arepas.clu","los.txt","tres.txt"]"#
+        );
+    })
+}
+
+#[test]
+fn gets_no_rows_by_every_skip_zero() {
+    Playground::setup("every_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+            EmptyFile("los.txt"),
+            EmptyFile("tres.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | get name
+                | every 0 --skip
+                | to json --raw
+            "#
+        ));
+
+        assert_eq!(actual.out, "[]");
+    })
+}
+
+#[test]
+fn gets_all_rows_by_every_one() {
+    Playground::setup("every_test_3", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+            EmptyFile("los.txt"),
+            EmptyFile("tres.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | get name
+                | every 1
+                | to json --raw
+            "#
+        ));
+
+        assert_eq!(
+            actual.out,
+            r#"["amigos.txt","arepas.clu","los.txt","tres.txt"]"#
+        );
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn gets_no_rows_by_every_skip_one() {
+    Playground::setup("every_test_4", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+            EmptyFile("los.txt"),
+            EmptyFile("tres.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | get name
+                | every 1 --skip
+                | to json --raw
+            "#
+        ));
+
+        assert_eq!(actual.out, "");
+    })
+}
+
+#[test]
+fn gets_first_row_by_every_too_much() {
+    Playground::setup("every_test_5", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+            EmptyFile("los.txt"),
+            EmptyFile("tres.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | get name
+                | every 999
+            "#
+        ));
+
+        let expected = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                echo [ amigos.txt ]
+            "#
+        ));
+
+        assert_eq!(actual.out, expected.out);
+    })
+}
+
+#[test]
+fn gets_all_rows_except_first_by_every_skip_too_much() {
+    Playground::setup("every_test_6", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+            EmptyFile("los.txt"),
+            EmptyFile("tres.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | get name
+                | every 999 --skip
+                | to json --raw
+            "#
+        ));
+
+        assert_eq!(actual.out, r#"["arepas.clu","los.txt","tres.txt"]"#);
+    })
+}
+
+#[test]
+fn gets_every_third_row() {
+    Playground::setup("every_test_7", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+            EmptyFile("los.txt"),
+            EmptyFile("quatro.txt"),
+            EmptyFile("tres.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | get name
+                | every 3
+                | to json --raw
+            "#
+        ));
+
+        assert_eq!(actual.out, r#"["amigos.txt","quatro.txt"]"#);
+    })
+}
+
+#[test]
+fn skips_every_third_row() {
+    Playground::setup("every_test_8", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+            EmptyFile("los.txt"),
+            EmptyFile("quatro.txt"),
+            EmptyFile("tres.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | get name
+                | every 3 --skip
+                | to json --raw
+            "#
+        ));
+
+        assert_eq!(actual.out, r#"["arepas.clu","los.txt","tres.txt"]"#);
+    })
+}

crates/nu-command/tests/commands/find.rs

@@ -0,0 +1,117 @@
+use nu_test_support::fs::Stub::EmptyFile;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn find_with_list_search_with_string() {
+    let actual = nu!(
+    cwd: ".", pipeline(
+    r#"
+        [moe larry curly] | find moe
+    "#
+    ));
+
+    assert_eq!(actual.out, "moe");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn find_with_list_search_with_char() {
+    let actual = nu!(
+    cwd: ".", pipeline(
+    r#"
+        [moe larry curly] | find l | to json
+    "#
+    ));
+
+    assert_eq!(actual.out, r#"["larry","curly"]"#);
+}
+
+#[test]
+fn find_with_list_search_with_number() {
+    let actual = nu!(
+    cwd: ".", pipeline(
+    r#"
+        [1 2 3 4 5] | find 3
+    "#
+    ));
+
+    assert_eq!(actual.out, "3");
+}
+
+#[test]
+fn find_with_string_search_with_string() {
+    let actual = nu!(
+    cwd: ".", pipeline(
+    r#"
+        echo Cargo.toml | find toml
+    "#
+    ));
+
+    assert_eq!(actual.out, "Cargo.toml");
+}
+
+#[test]
+fn find_with_string_search_with_string_not_found() {
+    let actual = nu!(
+    cwd: ".", pipeline(
+    r#"
+        [moe larry curly] | find shemp
+    "#
+    ));
+
+    assert_eq!(actual.out, "");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn find_with_filepath_search_with_string() {
+    Playground::setup("filepath_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+            EmptyFile("los.txt"),
+            EmptyFile("tres.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | get name
+                | find arep
+                | to json
+            "#
+        ));
+
+        assert_eq!(actual.out, r#""arepas.clu""#);
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn find_with_filepath_search_with_multiple_patterns() {
+    Playground::setup("filepath_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+            EmptyFile("los.txt"),
+            EmptyFile("tres.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | get name
+                | find arep ami
+                | to json
+            "#
+        ));
+
+        assert_eq!(actual.out, r#"["amigos.txt","arepas.clu"]"#);
+    })
+}

crates/nu-command/tests/commands/first.rs

@@ -0,0 +1,67 @@
+use nu_test_support::fs::Stub::EmptyFile;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn gets_first_rows_by_amount() {
+    Playground::setup("first_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("los.txt"),
+            EmptyFile("tres.txt"),
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | first 3
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "3");
+    })
+}
+
+#[test]
+fn gets_all_rows_if_amount_higher_than_all_rows() {
+    Playground::setup("first_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("los.txt"),
+            EmptyFile("tres.txt"),
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | first 99
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "4");
+    })
+}
+
+#[test]
+fn gets_first_row_when_no_amount_given() {
+    Playground::setup("first_test_3", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("caballeros.txt"), EmptyFile("arepas.clu")]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | first
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "1");
+    })
+}

crates/nu-command/tests/commands/flatten.rs

@@ -0,0 +1,192 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn flatten_nested_tables_with_columns() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+            echo [[origin, people]; [Ecuador, ('Andres' | wrap name)]]
+                 [[origin, people]; [Nu, ('nuno' | wrap name)]]
+            | flatten
+            | get name
+            | str collect ','
+        "#
+    ));
+
+    assert_eq!(actual.out, "Andres,nuno");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn flatten_nested_tables_that_have_many_columns() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+            echo [[origin, people]; [Ecuador, (echo [[name, meal]; ['Andres', 'arepa']])]]
+                 [[origin, people]; [USA, (echo [[name, meal]; ['Katz', 'nurepa']])]] 
+            | flatten
+            | get meal
+            | str collect ','
+        "#
+    ));
+
+    assert_eq!(actual.out, "arepa,nurepa");
+}
+
+#[test]
+fn flatten_nested_tables() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+            echo [[Andrés, Nicolás, Robalino]] | flatten | nth 1
+        "#
+    ));
+
+    assert_eq!(actual.out, "Nicolás");
+}
+
+#[test]
+fn flatten_row_column_explicitly() {
+    Playground::setup("flatten_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "katz.json",
+            r#"
+                [
+                    {
+                        "people": {
+                            "name": "Andres",
+                            "meal": "arepa"
+                        }
+                    },
+                    {
+                        "people": {
+                            "name": "Katz",
+                            "meal": "nurepa"
+                        }
+                    }
+                ]
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "open katz.json | flatten people | where name == Andres | length"
+        );
+
+        assert_eq!(actual.out, "1");
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn flatten_row_columns_having_same_column_names_flats_separately() {
+    Playground::setup("flatten_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "katz.json",
+            r#"
+                [
+                    {
+                        "people": {
+                            "name": "Andres",
+                            "meal": "arepa"
+                        },
+                        "city": [{"name": "Guayaquil"}, {"name": "Samborondón"}]
+                    },
+                    {
+                        "people": {
+                            "name": "Katz",
+                            "meal": "nurepa"
+                        },
+                        "city": [{"name": "Oregon"}, {"name": "Brooklin"}]
+                    }
+                ]
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "open katz.json | flatten | flatten people city | get city_name | length"
+        );
+
+        assert_eq!(actual.out, "4");
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn flatten_table_columns_explicitly() {
+    Playground::setup("flatten_test_3", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "katz.json",
+            r#"
+                [
+                    {
+                        "people": {
+                            "name": "Andres",
+                            "meal": "arepa"
+                        },
+                        "city": ["Guayaquil", "Samborondón"]
+                    },
+                    {
+                        "people": {
+                            "name": "Katz",
+                            "meal": "nurepa"
+                        },
+                        "city": ["Oregon", "Brooklin"]
+                    }
+                ]
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "open katz.json | flatten city | where people.name == Katz | length"
+        );
+
+        assert_eq!(actual.out, "2");
+    })
+}
+
+#[test]
+fn flatten_more_than_one_column_that_are_subtables_not_supported() {
+    Playground::setup("flatten_test_4", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "katz.json",
+            r#"
+                [
+                    {
+                        "people": {
+                            "name": "Andres",
+                            "meal": "arepa"
+                        }
+                        "tags": ["carbohydrate", "corn", "maiz"],
+                        "city": ["Guayaquil", "Samborondón"]
+                    },
+                    {
+                        "people": {
+                            "name": "Katz",
+                            "meal": "nurepa"
+                        },
+                        "tags": ["carbohydrate", "shell food", "amigos flavor"],
+                        "city": ["Oregon", "Brooklin"]
+                    }
+                ]
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "open katz.json | flatten tags city"
+        );
+
+        assert!(actual.err.contains("tried flattening"));
+        assert!(actual.err.contains("but is flattened already"));
+    })
+}

crates/nu-command/tests/commands/format.rs

@@ -0,0 +1,101 @@
+use nu_test_support::fs::Stub::{EmptyFile, FileWithContentToBeTrimmed};
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn creates_the_resulting_string_from_the_given_fields() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        open cargo_sample.toml
+            | get package
+            | format "{name} has license {license}"
+        "#
+    ));
+
+    assert_eq!(actual.out, "nu has license ISC");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn given_fields_can_be_column_paths() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        open cargo_sample.toml
+            | format "{package.name} is {package.description}"
+        "#
+    ));
+
+    assert_eq!(actual.out, "nu is a new type of shell");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn can_use_variables() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        open cargo_sample.toml
+            | format "{$it.package.name} is {$it.package.description}"
+        "#
+    ));
+
+    assert_eq!(actual.out, "nu is a new type of shell");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn format_filesize_works() {
+    Playground::setup("format_filesize_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("yehuda.txt"),
+            EmptyFile("jonathan.txt"),
+            EmptyFile("andres.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | format filesize size KB
+                | get size
+                | first
+            "#
+        ));
+
+        assert_eq!(actual.out, "0.0 KB");
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn format_filesize_works_with_nonempty_files() {
+    Playground::setup(
+        "format_filesize_works_with_nonempty_files",
+        |dirs, sandbox| {
+            sandbox.with_files(vec![FileWithContentToBeTrimmed(
+                "sample.toml",
+                r#"
+                    [dependency]
+                    name = "nu"
+                "#,
+            )]);
+
+            let actual = nu!(
+                cwd: dirs.test(),
+                "ls sample.toml | format filesize size B | get size | first"
+            );
+
+            #[cfg(not(windows))]
+            assert_eq!(actual.out, "25");
+
+            #[cfg(windows)]
+            assert_eq!(actual.out, "27");
+        },
+    )
+}

crates/nu-command/tests/commands/get.rs

@@ -0,0 +1,229 @@
+use nu_test_support::fs::Stub::FileWithContent;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn fetches_a_row() {
+    Playground::setup("get_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                nu_party_venue = "zion"
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open sample.toml
+                | get nu_party_venue
+            "#
+        ));
+
+        assert_eq!(actual.out, "zion");
+    })
+}
+
+#[test]
+fn fetches_by_index() {
+    Playground::setup("get_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                [package]
+                name = "nu"
+                version = "0.4.1"
+                authors = ["Yehuda Katz <wycats@gmail.com>", "Jonathan Turner <jonathan.d.turner@gmail.com>", "Andrés N. Robalino <andres@androbtech.com>"]
+                description = "When arepas shells are tasty and fun."
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open sample.toml
+                | get package.authors.2
+            "#
+        ));
+
+        assert_eq!(actual.out, "Andrés N. Robalino <andres@androbtech.com>");
+    })
+}
+#[test]
+fn fetches_by_column_path() {
+    Playground::setup("get_test_3", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                [package]
+                name = "nu"
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open sample.toml
+                | get package.name
+            "#
+        ));
+
+        assert_eq!(actual.out, "nu");
+    })
+}
+
+#[test]
+fn column_paths_are_either_double_quoted_or_regular_unquoted_words_separated_by_dot() {
+    Playground::setup("get_test_4", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                [package]
+                9999 = ["Yehuda Katz <wycats@gmail.com>", "Jonathan Turner <jonathan.d.turner@gmail.com>", "Andrés N. Robalino <andres@androbtech.com>"]
+                description = "When arepas shells are tasty and fun."
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open sample.toml
+                | get package."9999"
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "3");
+    })
+}
+
+#[test]
+fn fetches_more_than_one_column_path() {
+    Playground::setup("get_test_5", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                [[fortune_tellers]]
+                name = "Andrés N. Robalino"
+                arepas = 1
+
+                [[fortune_tellers]]
+                name = "Jonathan Turner"
+                arepas = 1
+
+                [[fortune_tellers]]
+                name = "Yehuda Katz"
+                arepas = 1
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open sample.toml
+                | get fortune_tellers.2.name fortune_tellers.0.name fortune_tellers.1.name
+                | nth 2
+            "#
+        ));
+
+        assert_eq!(actual.out, "Jonathan Turner");
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn errors_fetching_by_column_not_present() {
+    Playground::setup("get_test_6", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                [taconushell]
+                sentence_words = ["Yo", "quiero", "taconushell"]
+                [pizzanushell]
+                sentence-words = ["I", "want", "pizza"]
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open sample.toml
+                | get taco
+            "#
+        ));
+
+        assert!(actual.err.contains("Unknown column"),);
+        assert!(actual.err.contains("There isn't a column named 'taco'"),);
+        assert!(actual.err.contains("Perhaps you meant 'taconushell'?"),);
+        assert!(actual
+            .err
+            .contains("Columns available: pizzanushell, taconushell"),);
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn errors_fetching_by_column_using_a_number() {
+    Playground::setup("get_test_7", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                [spanish_lesson]
+                0 = "can only be fetched with 0 double quoted."
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open sample.toml
+                | get spanish_lesson.0
+            "#
+        ));
+
+        assert!(actual.err.contains("No rows available"),);
+        assert!(actual.err.contains("A row at '0' can't be indexed."),);
+        assert!(actual
+            .err
+            .contains("Appears to contain columns. Columns available: 0"),)
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn errors_fetching_by_index_out_of_bounds() {
+    Playground::setup("get_test_8", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                [spanish_lesson]
+                sentence_words = ["Yo", "quiero", "taconushell"]
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open sample.toml
+                | get spanish_lesson.sentence_words.3
+            "#
+        ));
+
+        assert!(actual.err.contains("Row not found"),);
+        assert!(actual.err.contains("There isn't a row indexed at 3"),);
+        assert!(actual.err.contains("The table only has 3 rows (0 to 2)"),)
+    })
+}
+
+#[test]
+fn quoted_column_access() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats",
+        r#"echo '[{"foo bar": {"baz": 4}}]' | from json | get "foo bar".baz "#
+    );
+
+    assert_eq!(actual.out, "4");
+}

crates/nu-command/tests/commands/group_by.rs

@@ -0,0 +1,99 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn groups() {
+    Playground::setup("group_by_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "los_tres_caballeros.csv",
+            r#"
+                first_name,last_name,rusty_at,type
+                Andrés,Robalino,10/11/2013,A
+                Jonathan,Turner,10/12/2013,B
+                Yehuda,Katz,10/11/2013,A
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open los_tres_caballeros.csv
+                | group-by rusty_at
+                | get "10/11/2013"
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "2");
+    })
+}
+
+#[test]
+fn errors_if_given_unknown_column_name() {
+    Playground::setup("group_by_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "los_tres_caballeros.json",
+            r#"
+                {
+                    "nu": {
+                        "committers": [
+                            {"name": "Andrés N. Robalino"},
+                            {"name": "Jonathan Turner"},
+                            {"name": "Yehuda Katz"}
+                        ],
+                        "releases": [
+                            {"version": "0.2"}
+                            {"version": "0.8"},
+                            {"version": "0.9999999"}
+                        ],
+                        "0xATYKARNU": [
+                            ["Th", "e", " "],
+                            ["BIG", " ", "UnO"],
+                            ["punto", "cero"]
+                        ]
+                    }
+                }
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open los_tres_caballeros.json
+                | group-by { get nu.releases.version }
+            "#
+        ));
+
+        assert!(actual
+            .err
+            .contains("requires a table with one value for grouping"));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn errors_if_block_given_evaluates_more_than_one_row() {
+    Playground::setup("group_by_test_3", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "los_tres_caballeros.csv",
+            r#"
+                first_name,last_name,rusty_at,type
+                Andrés,Robalino,10/11/2013,A
+                Jonathan,Turner,10/12/2013,B
+                Yehuda,Katz,10/11/2013,A
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open los_tres_caballeros.csv
+                | group-by ttype
+            "#
+        ));
+
+        assert!(actual.err.contains("Unknown column"));
+    })
+}

crates/nu-command/tests/commands/hash_/mod.rs

@@ -0,0 +1,122 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn base64_defaults_to_encoding_with_standard_character_type() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo 'username:password' | hash base64 
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "dXNlcm5hbWU6cGFzc3dvcmQ=");
+}
+
+#[test]
+fn base64_encode_characterset_binhex() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo 'username:password' | hash base64 --character_set binhex --encode
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "F@0NEPjJD97kE\'&bEhFZEP3");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn error_when_invalid_character_set_given() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo 'username:password' | hash base64 --character_set 'this is invalid' --encode
+        "#
+        )
+    );
+
+    assert!(actual
+        .err
+        .contains("this is invalid is not a valid character-set"));
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn base64_decode_characterset_binhex() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo "F@0NEPjJD97kE'&bEhFZEP3" | hash base64 --character_set binhex --decode
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "username:password");
+}
+
+#[test]
+fn error_invalid_decode_value() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo "this should not be a valid encoded value" | hash base64 --character_set url-safe --decode
+        "#
+        )
+    );
+
+    assert!(actual
+        .err
+        .contains("invalid base64 input for character set url-safe"));
+}
+
+#[test]
+fn error_use_both_flags() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo 'username:password' | hash base64 --encode --decode
+        "#
+        )
+    );
+
+    assert!(actual
+        .err
+        .contains("only one of --decode and --encode flags can be used"));
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn md5_works_with_file() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        open sample.db | hash md5 
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "4de97601d232c427977ef11db396c951");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn sha256_works_with_file() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+        open sample.db | hash sha256
+        "#
+        )
+    );
+
+    assert_eq!(
+        actual.out,
+        "2f5050e7eea415c1f3d80b5d93355efd15043ec9157a2bb167a9e73f2ae651f2"
+    );
+}

crates/nu-command/tests/commands/headers.rs

@@ -0,0 +1,35 @@
+use nu_test_support::{nu, pipeline};
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn headers_uses_first_row_as_header() {
+    let actual = nu!(
+    cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open sample_headers.xlsx
+            | get Sheet1
+            | headers
+            | get header0
+            | from json"#
+    ));
+
+    assert_eq!(actual.out, "r1c0r2c0")
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn headers_adds_missing_column_name() {
+    let actual = nu!(
+    cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open sample_headers.xlsx
+            | get Sheet1
+            | headers
+            | get Column1
+            | from json"#
+    ));
+
+    assert_eq!(actual.out, "r1c1r2c1")
+}

crates/nu-command/tests/commands/help.rs

@@ -0,0 +1,33 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn help_commands_length() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        help commands | length
+        "#
+    ));
+
+    let output = actual.out;
+    let output_int: i32 = output.parse().unwrap();
+    let is_positive = output_int.is_positive();
+    assert!(is_positive);
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn help_generate_docs_length() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        help generate_docs | flatten | length
+        "#
+    ));
+
+    let output = actual.out;
+    let output_int: i32 = output.parse().unwrap();
+    let is_positive = output_int.is_positive();
+    assert!(is_positive);
+}

crates/nu-command/tests/commands/histogram.rs

@@ -0,0 +1,117 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn summarizes_by_column_given() {
+    Playground::setup("histogram_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "los_tres_caballeros.csv",
+            r#"
+                first_name,last_name,rusty_at
+                Andrés,Robalino,Ecuador
+                Jonathan,Turner,Estados Unidos
+                Yehuda,Katz,Estados Unidos
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open los_tres_caballeros.csv
+                | histogram rusty_at countries
+                | where rusty_at == "Ecuador"
+                | get countries
+            "#
+        ));
+
+        assert_eq!(
+            actual.out,
+            "**************************************************"
+        );
+        // 50%
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn summarizes_by_values() {
+    Playground::setup("histogram_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "los_tres_caballeros.csv",
+            r#"
+                first_name,last_name,rusty_at
+                Andrés,Robalino,Ecuador
+                Jonathan,Turner,Estados Unidos
+                Yehuda,Katz,Estados Unidos
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open los_tres_caballeros.csv
+                | get rusty_at
+                | histogram
+                | where value == "Estados Unidos"
+                | get count
+            "#
+        ));
+
+        assert_eq!(actual.out, "2");
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn help() {
+    Playground::setup("histogram_test_3", |dirs, _sandbox| {
+        let help_command = nu!(
+        cwd: dirs.test(), pipeline(
+        r#"
+                help histogram
+            "#
+        ));
+
+        let help_short = nu!(
+        cwd: dirs.test(), pipeline(
+        r#"
+                histogram -h
+            "#
+        ));
+
+        let help_long = nu!(
+        cwd: dirs.test(), pipeline(
+        r#"
+                histogram --help
+            "#
+        ));
+
+        assert_eq!(help_short.out, help_command.out);
+        assert_eq!(help_long.out, help_command.out);
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn count() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+            echo [[bit];  [1] [0] [0] [0] [0] [0] [0] [1]]
+            | histogram bit
+            | sort-by count
+            | reject frequency
+            | to json
+        "#
+    ));
+
+    let bit_json = r#"[{"bit":"1","count":2,"percentage":"33.33%"},{"bit":"0","count":6,"percentage":"100.00%"}]"#;
+
+    assert_eq!(actual.out, bit_json);
+}

crates/nu-command/tests/commands/into_filesize.rs

@@ -0,0 +1,80 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn into_filesize_int() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        1 | into filesize
+        "#
+    ));
+
+    assert!(actual.out.contains("1 B"));
+}
+
+#[test]
+fn into_filesize_decimal() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        1.2 | into filesize
+        "#
+    ));
+
+    assert!(actual.out.contains("1 B"));
+}
+
+#[test]
+fn into_filesize_str() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        '2000' | into filesize
+        "#
+    ));
+
+    assert!(actual.out.contains("2.0 KiB"));
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn into_filesize_str_newline() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        "2000
+" | into filesize
+        "#
+    ));
+
+    assert!(actual.out.contains("2.0 KiB"));
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn into_filesize_str_many_newlines() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        "2000
+
+" | into filesize
+        "#
+    ));
+
+    assert!(actual.out.contains("2.0 KiB"));
+}
+
+#[test]
+fn into_filesize_filesize() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        3kib | into filesize
+        "#
+    ));
+
+    assert!(actual.out.contains("3.0 KiB"));
+}

crates/nu-command/tests/commands/into_int.rs

@@ -0,0 +1,37 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn into_int_filesize() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo 1kb | into int | each { $it / 1000 }
+        "#
+    ));
+
+    assert!(actual.out.contains('1'));
+}
+
+#[test]
+fn into_int_filesize2() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo 1kib | into int | each { $it / 1024 }
+        "#
+    ));
+
+    assert!(actual.out.contains('1'));
+}
+
+#[test]
+fn into_int_int() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo 1024 | into int | each { $it / 1024 }
+        "#
+    ));
+
+    assert!(actual.out.contains('1'));
+}

crates/nu-command/tests/commands/keep/mod.rs

@@ -0,0 +1,3 @@
+mod rows;
+mod until;
+mod while_;

crates/nu-command/tests/commands/keep/rows.rs

@@ -0,0 +1,31 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn rows() {
+    Playground::setup("keep_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "caballeros.csv",
+            r#"
+                name,lucky_code
+                Andrés,1
+                Jonathan,1
+                Jason,2
+                Yehuda,1
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open caballeros.csv
+                | keep 3
+                | get lucky_code
+                | math sum
+                "#
+        ));
+
+        assert_eq!(actual.out, "4");
+    })
+}

crates/nu-command/tests/commands/keep/until.rs

@@ -0,0 +1,52 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn condition_is_met() {
+    Playground::setup("keep_until_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "caballeros.txt",
+            r#"
+                CHICKEN SUMMARY                        report date: April 29th, 2020
+                --------------------------------------------------------------------
+                Chicken Collection,29/04/2020,30/04/2020,31/04/2020
+                Yellow Chickens,,,
+                Andrés,1,1,1
+                Jonathan,1,1,1
+                Jason,1,1,1
+                Yehuda,1,1,1
+                Blue Chickens,,,
+                Andrés,1,1,2
+                Jonathan,1,1,2
+                Jason,1,1,2
+                Yehuda,1,1,2
+                Red Chickens,,,
+                Andrés,1,1,3
+                Jonathan,1,1,3
+                Jason,1,1,3
+                Yehuda,1,1,3
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open --raw caballeros.txt
+                | lines 
+                | skip 2 
+                | str trim
+                | str collect (char nl) 
+                | from csv
+                | skip while "Chicken Collection" != "Blue Chickens"
+                | keep until "Chicken Collection" == "Red Chickens"
+                | skip 1
+                | into int "31/04/2020"
+                | get "31/04/2020"
+                | math sum
+                "#
+        ));
+
+        assert_eq!(actual.out, "8");
+    })
+}

crates/nu-command/tests/commands/keep/while_.rs

@@ -0,0 +1,51 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn condition_is_met() {
+    Playground::setup("keep_while_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "caballeros.txt",
+            r#"
+                CHICKEN SUMMARY                        report date: April 29th, 2020
+                --------------------------------------------------------------------
+                Chicken Collection,29/04/2020,30/04/2020,31/04/2020
+                Yellow Chickens,,,
+                Andrés,1,1,1
+                Jonathan,1,1,1
+                Jason,1,1,1
+                Yehuda,1,1,1
+                Blue Chickens,,,
+                Andrés,1,1,2
+                Jonathan,1,1,2
+                Jason,1,1,2
+                Yehuda,1,1,2
+                Red Chickens,,,
+                Andrés,1,1,3
+                Jonathan,1,1,3
+                Jason,1,1,3
+                Yehuda,1,1,3
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open --raw caballeros.txt
+                | lines 
+                | skip 2 
+                | str trim
+                | str collect (char nl) 
+                | from csv
+                | skip 1
+                | keep while "Chicken Collection" != "Blue Chickens"
+                | into int "31/04/2020"
+                | get "31/04/2020"
+                | math sum
+                "#
+        ));
+
+        assert_eq!(actual.out, "4");
+    })
+}

crates/nu-command/tests/commands/last.rs

@@ -0,0 +1,66 @@
+use nu_test_support::fs::Stub::EmptyFile;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn gets_the_last_row() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats",
+        "ls | sort-by name | last 1 | get name | str trim"
+    );
+
+    assert_eq!(actual.out, "utf16.ini");
+}
+
+#[test]
+fn gets_last_rows_by_amount() {
+    Playground::setup("last_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("los.txt"),
+            EmptyFile("tres.txt"),
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | last 3
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "3");
+    })
+}
+
+#[test]
+fn gets_last_row_when_no_amount_given() {
+    Playground::setup("last_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("caballeros.txt"), EmptyFile("arepas.clu")]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | last
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "1");
+    })
+}
+
+#[test]
+fn requests_more_rows_than_table_has() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        date | last 50 | length
+        "#
+    ));
+
+    assert_eq!(actual.out, "1");
+}

crates/nu-command/tests/commands/length.rs

@@ -0,0 +1,25 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn length_columns_in_cal_table() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        cal | length -c
+        "#
+    ));
+
+    assert_eq!(actual.out, "7");
+}
+
+#[test]
+fn length_columns_no_rows() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo [] | length -c
+        "#
+    ));
+
+    assert_eq!(actual.out, "0");
+}

crates/nu-command/tests/commands/lines.rs

@@ -0,0 +1,54 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn lines() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open cargo_sample.toml -r
+            | lines
+            | skip while $it != "[dependencies]"
+            | skip 1
+            | first 1
+            | split column "="
+            | get Column1
+            | str trim
+        "#
+    ));
+
+    assert_eq!(actual.out, "rustyline");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn lines_proper_buffering() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open lines_test.txt -r
+            | lines
+            | str length
+            | to json
+        "#
+    ));
+
+    assert_eq!(actual.out, "[8193,3]");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn lines_multi_value_split() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open sample-simple.json
+            | get first second
+            | lines
+            | length
+        "#
+    ));
+
+    assert_eq!(actual.out, "5");
+}

crates/nu-command/tests/commands/ls.rs

@@ -0,0 +1,352 @@
+use nu_test_support::fs::Stub::EmptyFile;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn lists_regular_files() {
+    Playground::setup("ls_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("yehuda.txt"),
+            EmptyFile("jonathan.txt"),
+            EmptyFile("andres.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "3");
+    })
+}
+
+#[test]
+fn lists_regular_files_using_asterisk_wildcard() {
+    Playground::setup("ls_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("los.txt"),
+            EmptyFile("tres.txt"),
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls *.txt
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "3");
+    })
+}
+
+#[test]
+fn lists_regular_files_using_question_mark_wildcard() {
+    Playground::setup("ls_test_3", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("yehuda.10.txt"),
+            EmptyFile("jonathan.10.txt"),
+            EmptyFile("andres.10.txt"),
+            EmptyFile("chicken_not_to_be_picked_up.100.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls *.??.txt
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "3");
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn lists_all_files_in_directories_from_stream() {
+    Playground::setup("ls_test_4", |dirs, sandbox| {
+        sandbox
+            .with_files(vec![EmptyFile("root1.txt"), EmptyFile("root2.txt")])
+            .within("dir_a")
+            .with_files(vec![
+                EmptyFile("yehuda.10.txt"),
+                EmptyFile("jonathan.10.txt"),
+            ])
+            .within("dir_b")
+            .with_files(vec![
+                EmptyFile("andres.10.txt"),
+                EmptyFile("chicken_not_to_be_picked_up.100.txt"),
+            ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                echo dir_a dir_b
+                | each { ls $it }
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "4");
+    })
+}
+
+#[test]
+fn does_not_fail_if_glob_matches_empty_directory() {
+    Playground::setup("ls_test_5", |dirs, sandbox| {
+        sandbox.within("dir_a");
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls dir_a
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "0");
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn fails_when_glob_doesnt_match() {
+    Playground::setup("ls_test_5", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("root1.txt"), EmptyFile("root2.txt")]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "ls root3*"
+        );
+
+        assert!(actual.err.contains("no matches found"));
+    })
+}
+
+#[test]
+fn list_files_from_two_parents_up_using_multiple_dots() {
+    Playground::setup("ls_test_6", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("yahuda.yaml"),
+            EmptyFile("jonathan.json"),
+            EmptyFile("andres.xml"),
+            EmptyFile("kevin.txt"),
+        ]);
+
+        sandbox.within("foo").mkdir("bar");
+
+        let actual = nu!(
+            cwd: dirs.test().join("foo/bar"),
+            r#"
+                ls ... | length
+            "#
+        );
+
+        assert_eq!(actual.out, "5");
+    })
+}
+
+#[test]
+fn lists_hidden_file_when_explicitly_specified() {
+    Playground::setup("ls_test_7", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("los.txt"),
+            EmptyFile("tres.txt"),
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+            EmptyFile(".testdotfile"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls .testdotfile
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "1");
+    })
+}
+
+#[test]
+fn lists_all_hidden_files_when_glob_contains_dot() {
+    Playground::setup("ls_test_8", |dirs, sandbox| {
+        sandbox
+            .with_files(vec![
+                EmptyFile("root1.txt"),
+                EmptyFile("root2.txt"),
+                EmptyFile(".dotfile1"),
+            ])
+            .within("dir_a")
+            .with_files(vec![
+                EmptyFile("yehuda.10.txt"),
+                EmptyFile("jonathan.10.txt"),
+                EmptyFile(".dotfile2"),
+            ])
+            .within("dir_b")
+            .with_files(vec![
+                EmptyFile("andres.10.txt"),
+                EmptyFile("chicken_not_to_be_picked_up.100.txt"),
+                EmptyFile(".dotfile3"),
+            ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls **/.*
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "3");
+    })
+}
+
+#[test]
+// TODO Remove this cfg value when we have an OS-agnostic way
+// of creating hidden files using the playground.
+#[cfg(unix)]
+fn lists_all_hidden_files_when_glob_does_not_contain_dot() {
+    Playground::setup("ls_test_8", |dirs, sandbox| {
+        sandbox
+            .with_files(vec![
+                EmptyFile("root1.txt"),
+                EmptyFile("root2.txt"),
+                EmptyFile(".dotfile1"),
+            ])
+            .within("dir_a")
+            .with_files(vec![
+                EmptyFile("yehuda.10.txt"),
+                EmptyFile("jonathan.10.txt"),
+                EmptyFile(".dotfile2"),
+            ])
+            .within(".dir_b")
+            .with_files(vec![
+                EmptyFile("andres.10.txt"),
+                EmptyFile("chicken_not_to_be_picked_up.100.txt"),
+                EmptyFile(".dotfile3"),
+            ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls **/*
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "5");
+    })
+}
+
+#[test]
+#[cfg(unix)]
+fn fails_with_ls_to_dir_without_permission() {
+    Playground::setup("ls_test_1", |dirs, sandbox| {
+        sandbox.within("dir_a").with_files(vec![
+            EmptyFile("yehuda.11.txt"),
+            EmptyFile("jonathan.10.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                chmod 000 dir_a; ls dir_a
+            "#
+        ));
+        assert!(actual
+            .err
+            .contains("The permissions of 0 do not allow access for this user"));
+    })
+}
+
+#[test]
+fn lists_files_including_starting_with_dot() {
+    Playground::setup("ls_test_9", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("yehuda.txt"),
+            EmptyFile("jonathan.txt"),
+            EmptyFile("andres.txt"),
+            EmptyFile(".hidden1.txt"),
+            EmptyFile(".hidden2.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls -a
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "5");
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn list_all_columns() {
+    Playground::setup("ls_test_all_columns", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("Leonardo.yaml"),
+            EmptyFile("Raphael.json"),
+            EmptyFile("Donatello.xml"),
+            EmptyFile("Michelangelo.txt"),
+        ]);
+        // Normal Operation
+        let actual = nu!(
+            cwd: dirs.test(),
+            "ls | get | to md"
+        );
+        let expected = ["name", "type", "size", "modified"].join("");
+        assert_eq!(actual.out, expected, "column names are incorrect for ls");
+        // Long
+        let actual = nu!(
+            cwd: dirs.test(),
+            "ls -l | get | to md"
+        );
+        let expected = {
+            #[cfg(unix)]
+            {
+                [
+                    "name",
+                    "type",
+                    "target",
+                    "num_links",
+                    "inode",
+                    "readonly",
+                    "mode",
+                    "uid",
+                    "group",
+                    "size",
+                    "created",
+                    "accessed",
+                    "modified",
+                ]
+                .join("")
+            }
+
+            #[cfg(windows)]
+            {
+                [
+                    "name", "type", "target", "readonly", "size", "created", "accessed", "modified",
+                ]
+                .join("")
+            }
+        };
+        assert_eq!(
+            actual.out, expected,
+            "column names are incorrect for ls long"
+        );
+    });
+}

crates/nu-command/tests/commands/math/avg.rs

@@ -0,0 +1,27 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn can_average_numbers() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+             open sgml_description.json
+             | get glossary.GlossDiv.GlossList.GlossEntry.Sections
+             | math avg
+         "#
+    ));
+
+    assert_eq!(actual.out, "101.5")
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn can_average_bytes() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats",
+        "ls | sort-by name | skip 1 | first 2 | get size | math avg | format \"{$it}\" "
+    );
+
+    assert_eq!(actual.out, "1.6 KB");
+}

crates/nu-command/tests/commands/math/eval.rs

@@ -0,0 +1,93 @@
+use nu_test_support::{nu, pipeline};
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn evaluates_two_plus_two() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        math eval "2 + 2"
+        "#
+    ));
+
+    assert!(actual.out.contains("4.0"));
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn evaluates_two_to_the_power_four() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo "2 ^ 4" | math eval
+        "#
+    ));
+
+    assert!(actual.out.contains("16.0"));
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn evaluates_three_multiplied_by_five() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo "3 * 5" | math eval
+        "#
+    ));
+
+    assert!(actual.out.contains("15.0"));
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn evaluates_twenty_four_divided_by_two() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo "24 / 2" | math eval
+        "#
+    ));
+
+    assert!(actual.out.contains("12.0"));
+}
+
+#[test]
+fn evaluates_twenty_eight_minus_seven() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo "28 - 7" | math eval
+        "#
+    ));
+
+    assert!(actual.out.contains("21"));
+}
+
+#[test]
+fn evaluates_pi() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        math eval pi
+        "#
+    ));
+
+    assert!(actual.out.contains("3.14"));
+}
+
+#[test]
+fn evaluates_tau() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        math eval tau
+        "#
+    ));
+
+    assert!(actual.out.contains("6.28"));
+}

crates/nu-command/tests/commands/math/median.rs

@@ -0,0 +1,40 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn median_numbers_with_even_rows() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+             echo [10 6 19 21 4]
+             | math median
+         "#
+    ));
+
+    assert_eq!(actual.out, "10")
+}
+
+#[test]
+fn median_numbers_with_odd_rows() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+             echo [3 8 9 12 12 15]
+             | math median
+         "#
+    ));
+
+    assert_eq!(actual.out, "10.5")
+}
+
+#[test]
+fn median_mixed_numbers() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+             echo [-11.5 -13.5 10]
+             | math median
+         "#
+    ));
+
+    assert_eq!(actual.out, "-11.5")
+}

crates/nu-command/tests/commands/math/mod.rs

@@ -0,0 +1,288 @@
+mod avg;
+mod eval;
+mod median;
+mod round;
+mod sqrt;
+mod sum;
+
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn one_arg() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            1
+        "#
+    ));
+
+    assert_eq!(actual.out, "1");
+}
+
+#[test]
+fn add() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            1 + 1
+        "#
+    ));
+
+    assert_eq!(actual.out, "2");
+}
+
+#[test]
+fn add_compound() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            1 + 2 + 2
+        "#
+    ));
+
+    assert_eq!(actual.out, "5");
+}
+
+#[test]
+fn precedence_of_operators() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            1 + 2 * 2
+        "#
+    ));
+
+    assert_eq!(actual.out, "5");
+}
+
+#[test]
+fn precedence_of_operators2() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            1 + 2 * 2 + 1
+        "#
+    ));
+
+    assert_eq!(actual.out, "6");
+}
+
+#[test]
+fn division_of_ints() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            4 / 2
+        "#
+    ));
+
+    assert_eq!(actual.out, "2");
+}
+
+#[test]
+fn division_of_ints2() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            1 / 4
+        "#
+    ));
+
+    assert_eq!(actual.out, "0.25");
+}
+
+#[test]
+fn error_zero_division_int_int() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            1 / 0
+        "#
+    ));
+
+    assert!(actual.err.contains("division by zero"));
+}
+
+#[test]
+fn error_zero_division_decimal_int() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            1.0 / 0
+        "#
+    ));
+
+    assert!(actual.err.contains("division by zero"));
+}
+
+#[test]
+fn error_zero_division_int_decimal() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            1 / 0.0
+        "#
+    ));
+
+    assert!(actual.err.contains("division by zero"));
+}
+
+#[test]
+fn error_zero_division_decimal_decimal() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            1.0 / 0.0
+        "#
+    ));
+
+    assert!(actual.err.contains("division by zero"));
+}
+
+#[test]
+fn proper_precedence_history() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            2 / 2 / 2 + 1
+        "#
+    ));
+
+    assert_eq!(actual.out, "1.5");
+}
+
+#[test]
+fn parens_precedence() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            4 * (6 - 3)
+        "#
+    ));
+
+    assert_eq!(actual.out, "12");
+}
+
+#[test]
+fn modulo() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            9 mod 2
+        "#
+    ));
+
+    assert_eq!(actual.out, "1");
+}
+
+#[test]
+fn duration_math() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            1wk + 1day
+        "#
+    ));
+
+    assert_eq!(actual.out, "8day");
+}
+
+#[test]
+fn duration_decimal_math() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            5.5day + 0.5day
+        "#
+    ));
+
+    assert_eq!(actual.out, "6day");
+}
+
+#[test]
+fn duration_math_with_nanoseconds() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            1wk + 10ns
+        "#
+    ));
+
+    assert_eq!(actual.out, "7day 10ns");
+}
+
+#[test]
+fn duration_decimal_math_with_nanoseconds() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            1.5wk + 10ns
+        "#
+    ));
+
+    assert_eq!(actual.out, "10day 10ns");
+}
+
+#[test]
+fn duration_math_with_negative() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            1day - 1wk
+        "#
+    ));
+
+    assert_eq!(actual.out, "-6day");
+}
+
+#[test]
+fn compound_comparison() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            4 > 3 && 2 > 1
+        "#
+    ));
+
+    assert_eq!(actual.out, "true");
+}
+
+#[test]
+fn compound_comparison2() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            4 < 3 || 2 > 1
+        "#
+    ));
+
+    assert_eq!(actual.out, "true");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn compound_where() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            echo '[{"a": 1, "b": 1}, {"a": 2, "b": 1}, {"a": 2, "b": 2}]' | from json | where a == 2 && b == 1 | to json
+        "#
+    ));
+
+    assert_eq!(actual.out, r#"{"a":2,"b":1}"#);
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn compound_where_paren() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            echo '[{"a": 1, "b": 1}, {"a": 2, "b": 1}, {"a": 2, "b": 2}]' | from json | where ($it.a == 2 && $it.b == 1) || $it.b == 2 | to json
+        "#
+    ));
+
+    assert_eq!(actual.out, r#"[{"a":2,"b":1},{"a":2,"b":2}]"#);
+}

crates/nu-command/tests/commands/math/round.rs

@@ -0,0 +1,21 @@
+use nu_test_support::nu;
+
+#[test]
+fn can_round_very_large_numbers() {
+    let actual = nu!(
+        cwd: ".",
+        "echo 18.1372544780074142289927665486772012345 | math round"
+    );
+
+    assert_eq!(actual.out, "18")
+}
+
+#[test]
+fn can_round_very_large_numbers_with_precision() {
+    let actual = nu!(
+        cwd: ".",
+        "echo 18.13725447800741422899276654867720121457878988 | math round -p 10"
+    );
+
+    assert_eq!(actual.out, "18.137254478")
+}

crates/nu-command/tests/commands/math/sqrt.rs

@@ -0,0 +1,35 @@
+use nu_test_support::nu;
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn can_sqrt_numbers() {
+    let actual = nu!(
+        cwd: ".",
+        "echo [0.25 2 4] | math sqrt | math sum"
+    );
+
+    assert_eq!(actual.out, "3.914213562373095048801688724209698078569671875376948073176679737990732478462107038850387534327641573");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn can_sqrt_irrational() {
+    let actual = nu!(
+        cwd: ".",
+        "echo 2 | math sqrt"
+    );
+
+    assert_eq!(actual.out, "1.414213562373095048801688724209698078569671875376948073176679737990732478462107038850387534327641573");
+}
+
+#[test]
+fn can_sqrt_perfect_square() {
+    let actual = nu!(
+        cwd: ".",
+        "echo 4 | math sqrt"
+    );
+
+    assert_eq!(actual.out, "2");
+}

crates/nu-command/tests/commands/math/sum.rs

@@ -0,0 +1,89 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+use std::str::FromStr;
+
+#[test]
+fn all() {
+    Playground::setup("sum_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "meals.json",
+            r#"
+                {
+                    meals: [
+                        {description: "1 large egg", calories: 90},
+                        {description: "1 cup white rice", calories: 250},
+                        {description: "1 tablespoon fish oil", calories: 108}
+                    ]
+                }
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open meals.json
+                | get meals
+                | get calories
+                | math sum
+            "#
+        ));
+
+        assert_eq!(actual.out, "448");
+    })
+}
+
+#[test]
+#[allow(clippy::unreadable_literal)]
+#[allow(clippy::float_cmp)]
+fn compute_sum_of_individual_row() -> Result<(), String> {
+    let answers_for_columns = [
+        ("cpu", 88.257434),
+        ("mem", 3032375296.),
+        ("virtual", 102579965952.),
+    ];
+    for (column_name, expected_value) in answers_for_columns {
+        let actual = nu!(
+            cwd: "tests/fixtures/formats/",
+            format!("open sample-ps-output.json | select {} | math sum | get {}", column_name, column_name)
+        );
+        let result =
+            f64::from_str(&actual.out).map_err(|_| String::from("Failed to parse float."))?;
+        assert_eq!(result, expected_value);
+    }
+    Ok(())
+}
+
+#[test]
+#[allow(clippy::unreadable_literal)]
+#[allow(clippy::float_cmp)]
+fn compute_sum_of_table() -> Result<(), String> {
+    let answers_for_columns = [
+        ("cpu", 88.257434),
+        ("mem", 3032375296.),
+        ("virtual", 102579965952.),
+    ];
+    for (column_name, expected_value) in answers_for_columns {
+        let actual = nu!(
+            cwd: "tests/fixtures/formats/",
+            format!("open sample-ps-output.json | select cpu mem virtual | math sum | get {}", column_name)
+        );
+        let result =
+            f64::from_str(&actual.out).map_err(|_| String::from("Failed to parse float."))?;
+        assert_eq!(result, expected_value);
+    }
+    Ok(())
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn sum_of_a_row_containing_a_table_is_an_error() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats/",
+        "open sample-sys-output.json | math sum"
+    );
+    assert!(actual
+        .err
+        .contains("Attempted to compute values that can't be operated on"));
+}

crates/nu-command/tests/commands/merge.rs

@@ -0,0 +1,44 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn row() {
+    Playground::setup("merge_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            FileWithContentToBeTrimmed(
+                "caballeros.csv",
+                r#"
+                name,country,luck
+                Andrés,Ecuador,0
+                Jonathan,USA,0
+                Jason,Canada,0
+                Yehuda,USA,0
+            "#,
+            ),
+            FileWithContentToBeTrimmed(
+                "new_caballeros.csv",
+                r#"
+                name,country,luck
+                Andrés Robalino,Guayaquil Ecuador,1
+                Jonathan Turner,New Zealand,1
+            "#,
+            ),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open caballeros.csv
+                | merge { open new_caballeros.csv }
+                | where country in ["Guayaquil Ecuador" "New Zealand"]
+                | get luck
+                | math sum
+                "#
+        ));
+
+        assert_eq!(actual.out, "2");
+    })
+}

crates/nu-command/tests/commands/mkdir.rs

@@ -0,0 +1,84 @@
+use nu_test_support::fs::files_exist_at;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+use std::path::Path;
+
+#[test]
+fn creates_directory() {
+    Playground::setup("mkdir_test_1", |dirs, _| {
+        nu!(
+            cwd: dirs.test(),
+            "mkdir my_new_directory"
+        );
+
+        let expected = dirs.test().join("my_new_directory");
+
+        assert!(expected.exists());
+    })
+}
+
+#[test]
+fn accepts_and_creates_directories() {
+    Playground::setup("mkdir_test_2", |dirs, _| {
+        nu!(
+            cwd: dirs.test(),
+            "mkdir dir_1 dir_2 dir_3"
+        );
+
+        assert!(files_exist_at(
+            vec![Path::new("dir_1"), Path::new("dir_2"), Path::new("dir_3")],
+            dirs.test()
+        ));
+    })
+}
+
+#[test]
+fn creates_intermediary_directories() {
+    Playground::setup("mkdir_test_3", |dirs, _| {
+        nu!(
+            cwd: dirs.test(),
+            "mkdir some_folder/another/deeper_one"
+        );
+
+        let expected = dirs.test().join("some_folder/another/deeper_one");
+
+        assert!(expected.exists());
+    })
+}
+
+#[test]
+fn create_directory_two_parents_up_using_multiple_dots() {
+    Playground::setup("mkdir_test_4", |dirs, sandbox| {
+        sandbox.within("foo").mkdir("bar");
+
+        nu!(
+            cwd: dirs.test().join("foo/bar"),
+            "mkdir .../boo"
+        );
+
+        let expected = dirs.test().join("boo");
+
+        assert!(expected.exists());
+    })
+}
+
+#[test]
+fn show_created_paths() {
+    Playground::setup("mkdir_test_2", |dirs, _| {
+        let actual = nu!(
+         cwd: dirs.test(),
+         pipeline(
+             r#"
+                 mkdir -s dir_1 dir_2 dir_3
+                 | length
+             "#
+        ));
+
+        assert!(files_exist_at(
+            vec![Path::new("dir_1"), Path::new("dir_2"), Path::new("dir_3")],
+            dirs.test()
+        ));
+
+        assert_eq!(actual.out, "3");
+    })
+}

crates/nu-command/tests/commands/mod.rs

@@ -0,0 +1,66 @@
+mod all;
+mod any;
+mod append;
+mod cal;
+mod cd;
+mod compact;
+mod cp;
+mod def;
+mod default;
+mod drop;
+mod each;
+mod echo;
+mod empty;
+mod enter;
+mod every;
+mod find;
+mod first;
+mod flatten;
+mod format;
+mod get;
+mod group_by;
+mod hash_;
+mod headers;
+mod help;
+mod histogram;
+mod into_filesize;
+mod into_int;
+mod keep;
+mod last;
+mod length;
+mod lines;
+mod ls;
+mod math;
+mod merge;
+mod mkdir;
+mod move_;
+mod open;
+mod parse;
+mod path;
+mod prepend;
+mod random;
+mod range;
+mod reduce;
+mod rename;
+mod reverse;
+mod rm;
+mod roll;
+mod rotate;
+mod save;
+mod select;
+mod semicolon;
+mod skip;
+mod sort_by;
+mod source;
+mod split_by;
+mod split_column;
+mod split_row;
+mod str_;
+mod touch;
+mod uniq;
+mod update;
+mod where_;
+mod which;
+mod with_env;
+mod wrap;
+mod zip;

crates/nu-command/tests/commands/move_/column.rs

@@ -0,0 +1,143 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn moves_a_column_before() {
+    Playground::setup("move_column_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "sample.csv",
+            r#"
+                column1,column2,column3,...,column98,column99,column100
+                -------,-------,-------,---,--------,   A    ,---------
+                -------,-------,-------,---,--------,   N    ,---------
+                -------,-------,-------,---,--------,   D    ,---------
+                -------,-------,-------,---,--------,   R    ,---------
+                -------,-------,-------,---,--------,   E    ,---------
+                -------,-------,-------,---,--------,   S    ,---------
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open sample.csv
+                | move column99 --before column1
+                | rename chars
+                | get chars
+                | str trim
+                | str collect
+            "#
+        ));
+
+        assert!(actual.out.contains("ANDRES"));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn moves_columns_before() {
+    Playground::setup("move_column_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "sample.csv",
+            r#"
+                column1,column2,column3,...,column98,column99,column100
+                -------,-------,   A   ,---,--------,   N    ,---------
+                -------,-------,   D   ,---,--------,   R    ,---------
+                -------,-------,   E   ,---,--------,   S    ,---------
+                -------,-------,   :   ,---,--------,   :    ,---------
+                -------,-------,   J   ,---,--------,   O    ,---------
+                -------,-------,   N   ,---,--------,   A    ,---------
+                -------,-------,   T   ,---,--------,   H    ,---------
+                -------,-------,   A   ,---,--------,   N    ,---------
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open sample.csv
+                | move column99 column3 --before column2
+                | rename _ chars_1 chars_2
+                | get chars_2 chars_1
+                | str trim
+                | str collect
+            "#
+        ));
+
+        assert!(actual.out.contains("ANDRES::JONATHAN"));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn moves_a_column_after() {
+    Playground::setup("move_column_test_3", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "sample.csv",
+            r#"
+                column1,column2,letters,...,column98,and_more,column100
+                -------,-------,   A   ,---,--------,   N    ,---------
+                -------,-------,   D   ,---,--------,   R    ,---------
+                -------,-------,   E   ,---,--------,   S    ,---------
+                -------,-------,   :   ,---,--------,   :    ,---------
+                -------,-------,   J   ,---,--------,   O    ,---------
+                -------,-------,   N   ,---,--------,   A    ,---------
+                -------,-------,   T   ,---,--------,   H    ,---------
+                -------,-------,   A   ,---,--------,   N    ,---------
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open sample.csv
+                | move letters --after and_more
+                | move letters and_more --before column2
+                | rename _ chars_1 chars_2
+                | get chars_1 chars_2
+                | str trim
+                | str collect
+            "#
+        ));
+
+        assert!(actual.out.contains("ANDRES::JONATHAN"));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn moves_columns_after() {
+    Playground::setup("move_column_test_4", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "sample.csv",
+            r#"
+                column1,column2,letters,...,column98,and_more,column100
+                -------,-------,   A   ,---,--------,   N    ,---------
+                -------,-------,   D   ,---,--------,   R    ,---------
+                -------,-------,   E   ,---,--------,   S    ,---------
+                -------,-------,   :   ,---,--------,   :    ,---------
+                -------,-------,   J   ,---,--------,   O    ,---------
+                -------,-------,   N   ,---,--------,   A    ,---------
+                -------,-------,   T   ,---,--------,   H    ,---------
+                -------,-------,   A   ,---,--------,   N    ,---------
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open sample.csv
+                | move letters and_more --after column1
+                | get
+                | nth 1 2
+                | str collect
+            "#
+        ));
+
+        assert!(actual.out.contains("lettersand_more"));
+    })
+}

crates/nu-command/tests/commands/move_/mod.rs

@@ -0,0 +1,2 @@
+mod column;
+mod mv;

crates/nu-command/tests/commands/move_/mv.rs

@@ -0,0 +1,371 @@
+use nu_test_support::fs::{files_exist_at, Stub::EmptyFile};
+use nu_test_support::nu;
+use nu_test_support::playground::Playground;
+
+#[test]
+fn moves_a_file() {
+    Playground::setup("mv_test_1", |dirs, sandbox| {
+        sandbox
+            .with_files(vec![EmptyFile("andres.txt")])
+            .mkdir("expected");
+
+        let original = dirs.test().join("andres.txt");
+        let expected = dirs.test().join("expected/yehuda.txt");
+
+        nu!(
+            cwd: dirs.test(),
+            "mv andres.txt expected/yehuda.txt"
+        );
+
+        assert!(!original.exists());
+        assert!(expected.exists());
+    })
+}
+
+#[test]
+fn overwrites_if_moving_to_existing_file() {
+    Playground::setup("mv_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("andres.txt"), EmptyFile("jonathan.txt")]);
+
+        let original = dirs.test().join("andres.txt");
+        let expected = dirs.test().join("jonathan.txt");
+
+        nu!(
+            cwd: dirs.test(),
+            "mv andres.txt jonathan.txt"
+        );
+
+        assert!(!original.exists());
+        assert!(expected.exists());
+    })
+}
+
+#[test]
+fn moves_a_directory() {
+    Playground::setup("mv_test_3", |dirs, sandbox| {
+        sandbox.mkdir("empty_dir");
+
+        let original_dir = dirs.test().join("empty_dir");
+        let expected = dirs.test().join("renamed_dir");
+
+        nu!(
+            cwd: dirs.test(),
+            "mv empty_dir renamed_dir"
+        );
+
+        assert!(!original_dir.exists());
+        assert!(expected.exists());
+    })
+}
+
+#[test]
+fn moves_the_file_inside_directory_if_path_to_move_is_existing_directory() {
+    Playground::setup("mv_test_4", |dirs, sandbox| {
+        sandbox
+            .with_files(vec![EmptyFile("jonathan.txt")])
+            .mkdir("expected");
+
+        let original_dir = dirs.test().join("jonathan.txt");
+        let expected = dirs.test().join("expected/jonathan.txt");
+
+        nu!(
+            cwd: dirs.test(),
+            "mv jonathan.txt expected"
+        );
+
+        assert!(!original_dir.exists());
+        assert!(expected.exists());
+    })
+}
+
+#[test]
+fn moves_the_directory_inside_directory_if_path_to_move_is_existing_directory() {
+    Playground::setup("mv_test_5", |dirs, sandbox| {
+        sandbox
+            .within("contributors")
+            .with_files(vec![EmptyFile("jonathan.txt")])
+            .mkdir("expected");
+
+        let original_dir = dirs.test().join("contributors");
+        let expected = dirs.test().join("expected/contributors");
+
+        nu!(
+            cwd: dirs.test(),
+            "mv contributors expected"
+        );
+
+        assert!(!original_dir.exists());
+        assert!(expected.exists());
+        assert!(files_exist_at(vec!["jonathan.txt"], expected))
+    })
+}
+
+#[test]
+fn moves_using_path_with_wildcard() {
+    Playground::setup("mv_test_7", |dirs, sandbox| {
+        sandbox
+            .within("originals")
+            .with_files(vec![
+                EmptyFile("andres.ini"),
+                EmptyFile("caco3_plastics.csv"),
+                EmptyFile("cargo_sample.toml"),
+                EmptyFile("jonathan.ini"),
+                EmptyFile("jonathan.xml"),
+                EmptyFile("sgml_description.json"),
+                EmptyFile("sample.ini"),
+                EmptyFile("utf16.ini"),
+                EmptyFile("yehuda.ini"),
+            ])
+            .mkdir("work_dir")
+            .mkdir("expected");
+
+        let work_dir = dirs.test().join("work_dir");
+        let expected = dirs.test().join("expected");
+
+        nu!(cwd: work_dir, "mv ../originals/*.ini ../expected");
+
+        assert!(files_exist_at(
+            vec!["yehuda.ini", "jonathan.ini", "sample.ini", "andres.ini",],
+            expected
+        ));
+    })
+}
+
+#[test]
+fn moves_using_a_glob() {
+    Playground::setup("mv_test_8", |dirs, sandbox| {
+        sandbox
+            .within("meals")
+            .with_files(vec![
+                EmptyFile("arepa.txt"),
+                EmptyFile("empanada.txt"),
+                EmptyFile("taquiza.txt"),
+            ])
+            .mkdir("work_dir")
+            .mkdir("expected");
+
+        let meal_dir = dirs.test().join("meals");
+        let work_dir = dirs.test().join("work_dir");
+        let expected = dirs.test().join("expected");
+
+        nu!(cwd: work_dir, "mv ../meals/* ../expected");
+
+        assert!(meal_dir.exists());
+        assert!(files_exist_at(
+            vec!["arepa.txt", "empanada.txt", "taquiza.txt",],
+            expected
+        ));
+    })
+}
+
+#[test]
+fn moves_a_directory_with_files() {
+    Playground::setup("mv_test_9", |dirs, sandbox| {
+        sandbox
+            .mkdir("vehicles/car")
+            .mkdir("vehicles/bicycle")
+            .with_files(vec![
+                EmptyFile("vehicles/car/car1.txt"),
+                EmptyFile("vehicles/car/car2.txt"),
+            ])
+            .with_files(vec![
+                EmptyFile("vehicles/bicycle/bicycle1.txt"),
+                EmptyFile("vehicles/bicycle/bicycle2.txt"),
+            ]);
+
+        let original_dir = dirs.test().join("vehicles");
+        let expected_dir = dirs.test().join("expected");
+
+        nu!(
+            cwd: dirs.test(),
+            "mv vehicles expected"
+        );
+
+        assert!(!original_dir.exists());
+        assert!(expected_dir.exists());
+        assert!(files_exist_at(
+            vec![
+                "car/car1.txt",
+                "car/car2.txt",
+                "bicycle/bicycle1.txt",
+                "bicycle/bicycle2.txt"
+            ],
+            expected_dir
+        ));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn errors_if_source_doesnt_exist() {
+    Playground::setup("mv_test_10", |dirs, sandbox| {
+        sandbox.mkdir("test_folder");
+        let actual = nu!(
+            cwd: dirs.test(),
+            "mv non-existing-file test_folder/"
+        );
+        assert!(actual.err.contains("Invalid file or pattern"));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn errors_if_destination_doesnt_exist() {
+    Playground::setup("mv_test_10_1", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("empty.txt")]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "mv empty.txt does/not/exist"
+        );
+
+        assert!(actual.err.contains("Destination directory does not exist"));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn errors_if_multiple_sources_but_destination_not_a_directory() {
+    Playground::setup("mv_test_10_2", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("file1.txt"),
+            EmptyFile("file2.txt"),
+            EmptyFile("file3.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "mv file?.txt not_a_dir"
+        );
+
+        assert!(actual
+            .err
+            .contains("Can only move multiple sources if destination is a directory"));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn errors_if_renaming_directory_to_an_existing_file() {
+    Playground::setup("mv_test_10_3", |dirs, sandbox| {
+        sandbox
+            .mkdir("mydir")
+            .with_files(vec![EmptyFile("empty.txt")]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "mv mydir empty.txt"
+        );
+
+        assert!(actual.err.contains("Cannot rename a directory to a file"));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn errors_if_moving_to_itself() {
+    Playground::setup("mv_test_10_4", |dirs, sandbox| {
+        sandbox.mkdir("mydir").mkdir("mydir/mydir_2");
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "mv mydir mydir/mydir_2/"
+        );
+
+        assert!(actual.err.contains("cannot move to itself"));
+    })
+}
+
+#[test]
+fn does_not_error_on_relative_parent_path() {
+    Playground::setup("mv_test_11", |dirs, sandbox| {
+        sandbox
+            .mkdir("first")
+            .with_files(vec![EmptyFile("first/william_hartnell.txt")]);
+
+        let original = dirs.test().join("first/william_hartnell.txt");
+        let expected = dirs.test().join("william_hartnell.txt");
+
+        nu!(
+            cwd: dirs.test().join("first"),
+            "mv william_hartnell.txt ./.."
+        );
+
+        assert!(!original.exists());
+        assert!(expected.exists());
+    })
+}
+
+#[test]
+fn move_files_using_glob_two_parents_up_using_multiple_dots() {
+    Playground::setup("mv_test_12", |dirs, sandbox| {
+        sandbox.within("foo").within("bar").with_files(vec![
+            EmptyFile("jonathan.json"),
+            EmptyFile("andres.xml"),
+            EmptyFile("yehuda.yaml"),
+            EmptyFile("kevin.txt"),
+            EmptyFile("many_more.ppl"),
+        ]);
+
+        nu!(
+            cwd: dirs.test().join("foo/bar"),
+            r#"
+                mv * ...
+            "#
+        );
+
+        let files = vec![
+            "yehuda.yaml",
+            "jonathan.json",
+            "andres.xml",
+            "kevin.txt",
+            "many_more.ppl",
+        ];
+
+        let original_dir = dirs.test().join("foo/bar");
+        let destination_dir = dirs.test();
+
+        assert!(files_exist_at(files.clone(), destination_dir));
+        assert!(!files_exist_at(files, original_dir))
+    })
+}
+
+#[test]
+fn move_file_from_two_parents_up_using_multiple_dots_to_current_dir() {
+    Playground::setup("cp_test_10", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("hello_there")]);
+        sandbox.within("foo").mkdir("bar");
+
+        nu!(
+            cwd: dirs.test().join("foo/bar"),
+            r#"
+                mv .../hello_there .
+            "#
+        );
+
+        let expected = dirs.test().join("foo/bar/hello_there");
+        let original = dirs.test().join("hello_there");
+
+        assert!(expected.exists());
+        assert!(!original.exists());
+    })
+}
+
+#[test]
+fn does_not_error_when_some_file_is_moving_into_itself() {
+    Playground::setup("mv_test_13", |dirs, sandbox| {
+        sandbox.mkdir("11").mkdir("12");
+
+        let original_dir = dirs.test().join("11");
+        let expected = dirs.test().join("12/11");
+        nu!(cwd: dirs.test(), "mv 1* 12");
+
+        assert!(!original_dir.exists());
+        assert!(expected.exists());
+    })
+}

crates/nu-command/tests/commands/nth.rs

@@ -0,0 +1,37 @@
+#[test]
+fn selects_a_row() {
+    Playground::setup("nth_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("notes.txt"), EmptyFile("arepas.txt")]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | sort-by name
+                | nth 0
+                | get name
+            "#
+        ));
+
+        assert_eq!(actual.out, "arepas.txt");
+    });
+}
+
+#[test]
+fn selects_many_rows() {
+    Playground::setup("nth_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("notes.txt"), EmptyFile("arepas.txt")]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | get name
+                | nth 1 0
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "2");
+    });
+}

crates/nu-command/tests/commands/open.rs

@@ -0,0 +1,245 @@
+use nu_test_support::fs::Stub::EmptyFile;
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn parses_csv() {
+    Playground::setup("open_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "nu.zion.csv",
+            r#"
+                    author,lang,source
+                    Jonathan Turner,Rust,New Zealand
+                    Andres N. Robalino,Rust,Ecuador
+                    Yehuda Katz,Rust,Estados Unidos
+                "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open nu.zion.csv
+                | where author == "Andres N. Robalino"
+                | get source
+            "#
+        ));
+
+        assert_eq!(actual.out, "Ecuador");
+    })
+}
+
+// sample.bson has the following format:
+// ━━━━━━━━━━┯━━━━━━━━━━━
+//  _id      │ root
+// ──────────┼───────────
+//  [object] │ [9 items]
+// ━━━━━━━━━━┷━━━━━━━━━━━
+//
+// the root value is:
+// ━━━┯━━━━━━━━━━━━━━━━━━━┯━━━━━━━━━━━━━━━━━━━━━━━━━┯━━━━━━━━━━┯━━━━━━━━━━
+//  # │ _id               │ a                       │ b        │ c
+// ───┼───────────────────┼─────────────────────────┼──────────┼──────────
+//  0 │ [object]          │       1.000000000000000 │ hello    │ [2 items]
+//  1 │ [object]          │       42.00000000000000 │ whel     │ hello
+//  2 │ [object]          │ [object]                │          │
+//  3 │ [object]          │                         │ [object] │
+//  4 │ [object]          │                         │          │ [object]
+//  5 │ [object]          │                         │          │ [object]
+//  6 │ [object]          │ [object]                │ [object] │
+//  7 │ [object]          │ <date value>            │ [object] │
+//  8 │ 1.000000          │ <decimal value>         │ [object] │
+//
+// The decimal value is supposed to be π, but is currently wrong due to
+// what appears to be an issue in the bson library that is under investigation.
+//
+
+#[cfg(feature = "bson")]
+#[test]
+fn parses_bson() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats",
+        "open sample.bson | get root | nth 0 | get b"
+    );
+
+    assert_eq!(actual.out, "hello");
+}
+
+#[cfg(feature = "bson")]
+#[test]
+fn parses_more_bson_complexity() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open sample.bson
+            | get root
+            | nth 6
+            | get b
+            | get '$binary_subtype'
+        "#
+    ));
+
+    assert_eq!(actual.out, "function");
+}
+
+// sample.db has the following format:
+//
+// ━━━┯━━━━━━━━━━━━┯━━━━━━━━━━━━━━
+//  # │ table_name │ table_values
+// ───┼────────────┼──────────────
+//  0 │ strings    │ [6 items]
+//  1 │ ints       │ [5 items]
+//  2 │ floats     │ [4 items]
+// ━━━┷━━━━━━━━━━━━┷━━━━━━━━━━━━━━
+//
+// In this case, this represents a sqlite database
+// with three tables named `strings`, `ints`, and `floats`.
+// The table_values represent the values for the tables:
+//
+// ━━━━┯━━━━━━━┯━━━━━━━━━━┯━━━━━━┯━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+//  #  │ x     │ y        │ z    │ f
+// ────┼───────┼──────────┼──────┼──────────────────────────────────────────────────────────────────────
+//   0 │ hello │ <binary> │      │
+//   1 │ hello │ <binary> │      │
+//   2 │ hello │ <binary> │      │
+//   3 │ hello │ <binary> │      │
+//   4 │ world │ <binary> │      │
+//   5 │ world │ <binary> │      │
+//   6 │       │          │    1 │
+//   7 │       │          │   42 │
+//   8 │       │          │  425 │
+//   9 │       │          │ 4253 │
+//  10 │       │          │      │
+//  11 │       │          │      │                                                    3.400000000000000
+//  12 │       │          │      │                                                    3.141592650000000
+//  13 │       │          │      │                                                    23.00000000000000
+//  14 │       │          │      │ this string that doesn't really belong here but sqlite is what it is
+// ━━━━┷━━━━━━━┷━━━━━━━━━━┷━━━━━━┷━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+//
+// We can see here that each table has different columns. `strings` has `x` and `y`, while
+// `ints` has just `z`, and `floats` has only the column `f`. This means, in general, when working
+// with sqlite, one will want to select a single table, e.g.:
+//
+// open sample.db | nth 1 | get table_values
+// ━━━┯━━━━━━
+//  # │ z
+// ───┼──────
+//  0 │    1
+//  1 │   42
+//  2 │  425
+//  3 │ 4253
+//  4 │
+// ━━━┷━━━━━━
+
+#[cfg(feature = "sqlite")]
+#[test]
+fn parses_sqlite() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open sample.db
+            | get table_values
+            | nth 2
+            | get x
+        "#
+    ));
+
+    assert_eq!(actual.out, "hello");
+}
+
+#[test]
+fn parses_toml() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats",
+        "open cargo_sample.toml | get package.edition"
+    );
+
+    assert_eq!(actual.out, "2018");
+}
+
+#[test]
+fn parses_tsv() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open caco3_plastics.tsv
+            | first 1
+            | get origin
+        "#
+    ));
+
+    assert_eq!(actual.out, "SPAIN")
+}
+
+#[test]
+fn parses_json() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open sgml_description.json
+            | get glossary.GlossDiv.GlossList.GlossEntry.GlossSee
+        "#
+    ));
+
+    assert_eq!(actual.out, "markup")
+}
+
+#[test]
+fn parses_ini() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats",
+        "open sample.ini | get SectionOne.integer"
+    );
+
+    assert_eq!(actual.out, "1234")
+}
+
+#[test]
+fn parses_utf16_ini() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats",
+        "open ./utf16.ini --raw | decode utf-16 | from ini | rename info | get info | get IconIndex"
+    );
+
+    assert_eq!(actual.out, "-236")
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn errors_if_file_not_found() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats",
+        "open i_dont_exist.txt"
+    );
+    let expected = "Cannot find file";
+    assert!(
+        actual.err.contains(expected),
+        "Error:\n{}\ndoes not contain{}",
+        actual.err,
+        expected
+    );
+}
+
+// FIXME: jt: I think `open` on a directory is confusing. We should make discuss this one a bit more
+#[ignore]
+#[test]
+fn open_dir_is_ls() {
+    Playground::setup("open_dir", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("yehuda.txt"),
+            EmptyFile("jonathan.txt"),
+            EmptyFile("andres.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open .
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "3");
+    })
+}

crates/nu-command/tests/commands/parse.rs

@@ -0,0 +1,191 @@
+use nu_test_support::fs::Stub;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+mod simple {
+    use super::*;
+
+    // FIXME: jt: needs more work
+    #[ignore]
+    #[test]
+    fn extracts_fields_from_the_given_the_pattern() {
+        Playground::setup("parse_test_1", |dirs, sandbox| {
+            sandbox.with_files(vec![Stub::FileWithContentToBeTrimmed(
+                "key_value_separated_arepa_ingredients.txt",
+                r#"
+                    VAR1=Cheese
+                    VAR2=JonathanParsed
+                    VAR3=NushellSecretIngredient
+                "#,
+            )]);
+
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                    open key_value_separated_arepa_ingredients.txt
+                    | lines
+                    | each { echo $it | parse "{Name}={Value}" }
+                    | nth 1
+                    | get Value
+                "#
+            ));
+
+            assert_eq!(actual.out, "JonathanParsed");
+        })
+    }
+
+    #[test]
+    fn double_open_curly_evalutes_to_a_single_curly() {
+        Playground::setup("parse_test_regex_2", |dirs, _sandbox| {
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                    echo "{abc}123"
+                    | parse "{{abc}{name}"
+                    | get name
+                "#
+            ));
+
+            assert_eq!(actual.out, "123");
+        })
+    }
+
+    #[test]
+    fn properly_escapes_text() {
+        Playground::setup("parse_test_regex_3", |dirs, _sandbox| {
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                    echo "(abc)123"
+                    | parse "(abc){name}"
+                    | get name
+                "#
+            ));
+
+            assert_eq!(actual.out, "123");
+        })
+    }
+
+    #[test]
+    fn properly_captures_empty_column() {
+        Playground::setup("parse_test_regex_4", |dirs, _sandbox| {
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                    echo ["1:INFO:component:all is well" "2:ERROR::something bad happened"]
+                    | parse "{timestamp}:{level}:{tag}:{entry}"
+                    | get entry
+                    | nth 1
+                "#
+            ));
+
+            assert_eq!(actual.out, "something bad happened");
+        })
+    }
+
+    // FIXME: jt: needs more work
+    #[ignore]
+    #[test]
+    fn errors_when_missing_closing_brace() {
+        Playground::setup("parse_test_regex_5", |dirs, _sandbox| {
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                    echo "(abc)123"
+                    | parse "(abc){name"
+                    | get name
+                "#
+            ));
+
+            assert!(actual.err.contains("invalid parse pattern"));
+        })
+    }
+}
+
+mod regex {
+    use super::*;
+
+    fn nushell_git_log_oneline<'a>() -> Vec<Stub<'a>> {
+        vec![Stub::FileWithContentToBeTrimmed(
+            "nushell_git_log_oneline.txt",
+            r#"
+                ae87582c Fix missing invocation errors (#1846)
+                b89976da let format access variables also (#1842)
+            "#,
+        )]
+    }
+
+    #[test]
+    fn extracts_fields_with_all_named_groups() {
+        Playground::setup("parse_test_regex_1", |dirs, sandbox| {
+            sandbox.with_files(nushell_git_log_oneline());
+
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                    open nushell_git_log_oneline.txt
+                    | parse --regex "(?P<Hash>\w+) (?P<Message>.+) \(#(?P<PR>\d+)\)"
+                    | nth 1
+                    | get PR
+                "#
+            ));
+
+            assert_eq!(actual.out, "1842");
+        })
+    }
+
+    #[test]
+    fn extracts_fields_with_all_unnamed_groups() {
+        Playground::setup("parse_test_regex_2", |dirs, sandbox| {
+            sandbox.with_files(nushell_git_log_oneline());
+
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                    open nushell_git_log_oneline.txt
+                    | parse --regex "(\w+) (.+) \(#(\d+)\)"
+                    | nth 1
+                    | get Capture1
+                "#
+            ));
+
+            assert_eq!(actual.out, "b89976da");
+        })
+    }
+
+    #[test]
+    fn extracts_fields_with_named_and_unnamed_groups() {
+        Playground::setup("parse_test_regex_3", |dirs, sandbox| {
+            sandbox.with_files(nushell_git_log_oneline());
+
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                    open nushell_git_log_oneline.txt
+                    | parse --regex "(?P<Hash>\w+) (.+) \(#(?P<PR>\d+)\)"
+                    | nth 1
+                    | get Capture2
+                "#
+            ));
+
+            assert_eq!(actual.out, "let format access variables also");
+        })
+    }
+
+    #[test]
+    fn errors_with_invalid_regex() {
+        Playground::setup("parse_test_regex_1", |dirs, sandbox| {
+            sandbox.with_files(nushell_git_log_oneline());
+
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                    open nushell_git_log_oneline.txt
+                    | parse --regex "(?P<Hash>\w+ unfinished capture group"
+                "#
+            ));
+
+            assert!(actual.err.contains("unclosed group"));
+        })
+    }
+}

crates/nu-command/tests/commands/path/basename.rs

@@ -0,0 +1,83 @@
+use nu_test_support::{nu, pipeline};
+
+use super::join_path_sep;
+
+#[test]
+fn returns_basename_of_empty_input() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "" 
+            | path basename
+        "#
+    ));
+
+    assert_eq!(actual.out, "");
+}
+
+#[test]
+fn replaces_basename_of_empty_input() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "" 
+            | path basename -r newname.txt
+        "#
+    ));
+
+    assert_eq!(actual.out, "newname.txt");
+}
+
+#[test]
+fn returns_basename_of_path_ending_with_dot() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "some/file.txt/." 
+            | path basename 
+        "#
+    ));
+
+    assert_eq!(actual.out, "file.txt");
+}
+
+#[test]
+fn replaces_basename_of_path_ending_with_dot() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "some/file.txt/." 
+            | path basename -r viking.txt
+        "#
+    ));
+
+    let expected = join_path_sep(&["some", "viking.txt"]);
+    assert_eq!(actual.out, expected);
+}
+
+#[test]
+fn returns_basename_of_path_ending_with_double_dot() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "some/file.txt/.." 
+            | path basename 
+        "#
+    ));
+
+    assert_eq!(actual.out, "");
+}
+
+#[test]
+fn replaces_basename_of_path_ending_with_double_dot() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "some/file.txt/.." 
+            | path basename -r eggs
+        "#
+    ));
+
+    let expected = join_path_sep(&["some/file.txt/..", "eggs"]);
+    assert_eq!(actual.out, expected);
+}

crates/nu-command/tests/commands/path/dirname.rs

@@ -0,0 +1,137 @@
+use nu_test_support::{nu, pipeline};
+
+use super::join_path_sep;
+
+#[test]
+fn returns_dirname_of_empty_input() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "" 
+            | path dirname
+        "#
+    ));
+
+    assert_eq!(actual.out, "");
+}
+
+#[test]
+fn replaces_dirname_of_empty_input() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "" 
+            | path dirname -r newdir
+        "#
+    ));
+
+    assert_eq!(actual.out, "newdir");
+}
+
+#[test]
+fn returns_dirname_of_path_ending_with_dot() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "some/dir/." 
+            | path dirname 
+        "#
+    ));
+
+    assert_eq!(actual.out, "some");
+}
+
+#[test]
+fn replaces_dirname_of_path_ending_with_dot() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "some/dir/." 
+            | path dirname -r eggs
+        "#
+    ));
+
+    let expected = join_path_sep(&["eggs", "dir"]);
+    assert_eq!(actual.out, expected);
+}
+
+#[test]
+fn returns_dirname_of_path_ending_with_double_dot() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "some/dir/.." 
+            | path dirname 
+        "#
+    ));
+
+    assert_eq!(actual.out, "some/dir");
+}
+
+#[test]
+fn replaces_dirname_of_path_with_double_dot() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "some/dir/.." 
+            | path dirname -r eggs
+        "#
+    ));
+
+    let expected = join_path_sep(&["eggs", ".."]);
+    assert_eq!(actual.out, expected);
+}
+
+#[test]
+fn returns_dirname_of_zero_levels() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "some/dir/with/spam.txt"
+            | path dirname -n 0
+        "#
+    ));
+
+    assert_eq!(actual.out, "some/dir/with/spam.txt");
+}
+
+#[test]
+fn replaces_dirname_of_zero_levels_with_empty_string() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "some/dir/with/spam.txt"
+            | path dirname -n 0 -r ""
+        "#
+    ));
+
+    assert_eq!(actual.out, "");
+}
+
+#[test]
+fn replaces_dirname_of_more_levels() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "some/dir/with/spam.txt"
+            | path dirname -r eggs -n 2
+        "#
+    ));
+
+    let expected = join_path_sep(&["eggs", "with/spam.txt"]);
+    assert_eq!(actual.out, expected);
+}
+
+#[test]
+fn replaces_dirname_of_way_too_many_levels() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "some/dir/with/spam.txt"
+            | path dirname -r eggs -n 999
+        "#
+    ));
+
+    let expected = join_path_sep(&["eggs", "some/dir/with/spam.txt"]);
+    assert_eq!(actual.out, expected);
+}

crates/nu-command/tests/commands/path/exists.rs

@@ -0,0 +1,55 @@
+use nu_test_support::fs::Stub::EmptyFile;
+use nu_test_support::nu;
+use nu_test_support::playground::Playground;
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn checks_if_existing_file_exists() {
+    Playground::setup("path_exists_1", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "echo spam.txt | path exists"
+        );
+
+        assert_eq!(actual.out, "true");
+    })
+}
+
+#[test]
+fn checks_if_missing_file_exists() {
+    Playground::setup("path_exists_2", |dirs, _| {
+        let actual = nu!(
+            cwd: dirs.test(),
+            "echo spam.txt | path exists"
+        );
+
+        assert_eq!(actual.out, "false");
+    })
+}
+
+#[test]
+fn checks_if_dot_exists() {
+    Playground::setup("path_exists_3", |dirs, _| {
+        let actual = nu!(
+            cwd: dirs.test(),
+            "echo '.' | path exists"
+        );
+
+        assert_eq!(actual.out, "true");
+    })
+}
+
+#[test]
+fn checks_if_double_dot_exists() {
+    Playground::setup("path_exists_4", |dirs, _| {
+        let actual = nu!(
+            cwd: dirs.test(),
+            "echo '..' | path exists"
+        );
+
+        assert_eq!(actual.out, "true");
+    })
+}

crates/nu-command/tests/commands/path/expand.rs

@@ -0,0 +1,78 @@
+use nu_test_support::fs::Stub::EmptyFile;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+use std::path::PathBuf;
+
+#[test]
+fn expands_path_with_dot() {
+    Playground::setup("path_expand_1", |dirs, sandbox| {
+        sandbox
+            .within("menu")
+            .with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                echo "menu/./spam.txt" 
+                | path expand
+            "#
+        ));
+
+        let expected = dirs.test.join("menu").join("spam.txt");
+        assert_eq!(PathBuf::from(actual.out), expected);
+    })
+}
+
+#[test]
+fn expands_path_with_double_dot() {
+    Playground::setup("path_expand_2", |dirs, sandbox| {
+        sandbox
+            .within("menu")
+            .with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                echo "menu/../menu/spam.txt" 
+                | path expand
+            "#
+        ));
+
+        let expected = dirs.test.join("menu").join("spam.txt");
+        assert_eq!(PathBuf::from(actual.out), expected);
+    })
+}
+
+#[cfg(windows)]
+mod windows {
+    use super::*;
+
+    #[test]
+    fn expands_path_with_tilde_backward_slash() {
+        Playground::setup("path_expand_2", |dirs, _| {
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                    echo "~\tmp.txt" | path expand
+                "#
+            ));
+
+            assert!(!PathBuf::from(actual.out).starts_with("~"));
+        })
+    }
+
+    #[test]
+    fn win_expands_path_with_tilde_forward_slash() {
+        Playground::setup("path_expand_2", |dirs, _| {
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                    echo "~/tmp.txt" | path expand
+                "#
+            ));
+
+            assert!(!PathBuf::from(actual.out).starts_with("~"));
+        })
+    }
+}

crates/nu-command/tests/commands/path/join.rs

@@ -0,0 +1,59 @@
+use nu_test_support::{nu, pipeline};
+
+use super::join_path_sep;
+
+#[test]
+fn returns_path_joined_with_column_path() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo [ [name]; [eggs] ]
+            | path join spam.txt -c [ name ]
+            | get name
+        "#
+    ));
+
+    let expected = join_path_sep(&["eggs", "spam.txt"]);
+    assert_eq!(actual.out, expected);
+}
+
+#[test]
+fn returns_path_joined_from_list() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo [ home viking spam.txt ]
+            | path join
+        "#
+    ));
+
+    let expected = join_path_sep(&["home", "viking", "spam.txt"]);
+    assert_eq!(actual.out, expected);
+}
+
+#[test]
+fn appends_slash_when_joined_with_empty_path() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "/some/dir"
+            | path join ''
+        "#
+    ));
+
+    let expected = join_path_sep(&["/some/dir", ""]);
+    assert_eq!(actual.out, expected);
+}
+
+#[test]
+fn returns_joined_path_when_joining_empty_path() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo ""
+            | path join foo.txt
+        "#
+    ));
+
+    assert_eq!(actual.out, "foo.txt");
+}

crates/nu-command/tests/commands/path/mod.rs

@@ -0,0 +1,34 @@
+mod basename;
+mod dirname;
+mod exists;
+mod expand;
+mod join;
+mod parse;
+mod split;
+mod type_;
+
+use std::path::MAIN_SEPARATOR;
+
+/// Helper function that joins string literals with '/' or '\', based on host OS
+fn join_path_sep(pieces: &[&str]) -> String {
+    let sep_string = String::from(MAIN_SEPARATOR);
+    pieces.join(&sep_string)
+}
+
+#[cfg(windows)]
+#[test]
+fn joins_path_on_windows() {
+    let pieces = ["sausage", "bacon", "spam"];
+    let actual = join_path_sep(&pieces);
+
+    assert_eq!(&actual, "sausage\\bacon\\spam");
+}
+
+#[cfg(not(windows))]
+#[test]
+fn joins_path_on_other_than_windows() {
+    let pieces = ["sausage", "bacon", "spam"];
+    let actual = join_path_sep(&pieces);
+
+    assert_eq!(&actual, "sausage/bacon/spam");
+}

crates/nu-command/tests/commands/path/parse.rs

@@ -0,0 +1,138 @@
+use nu_test_support::{nu, pipeline};
+
+#[cfg(windows)]
+#[test]
+fn parses_single_path_prefix() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo 'C:\users\viking\spam.txt'
+            | path parse
+            | get prefix
+        "#
+    ));
+
+    assert_eq!(actual.out, "C:");
+}
+
+#[test]
+fn parses_single_path_parent() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo 'home/viking/spam.txt'
+            | path parse
+            | get parent
+        "#
+    ));
+
+    assert_eq!(actual.out, "home/viking");
+}
+
+#[test]
+fn parses_single_path_stem() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo 'home/viking/spam.txt'
+            | path parse
+            | get stem
+        "#
+    ));
+
+    assert_eq!(actual.out, "spam");
+}
+
+#[test]
+fn parses_custom_extension_gets_extension() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo 'home/viking/spam.tar.gz'
+            | path parse -e tar.gz
+            | get extension
+        "#
+    ));
+
+    assert_eq!(actual.out, "tar.gz");
+}
+
+#[test]
+fn parses_custom_extension_gets_stem() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo 'home/viking/spam.tar.gz'
+            | path parse -e tar.gz
+            | get stem
+        "#
+    ));
+
+    assert_eq!(actual.out, "spam");
+}
+
+#[test]
+fn parses_ignoring_extension_gets_extension() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo 'home/viking/spam.tar.gz'
+            | path parse -e ''
+            | get extension
+        "#
+    ));
+
+    assert_eq!(actual.out, "");
+}
+
+#[test]
+fn parses_ignoring_extension_gets_stem() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo 'home/viking/spam.tar.gz'
+            | path parse -e ""
+            | get stem
+        "#
+    ));
+
+    assert_eq!(actual.out, "spam.tar.gz");
+}
+
+#[test]
+fn parses_column_path_extension() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo [[home, barn]; ['home/viking/spam.txt', 'barn/cow/moo.png']]
+            | path parse -c [ home barn ]
+            | get barn
+            | get extension
+        "#
+    ));
+
+    assert_eq!(actual.out, "png");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn parses_into_correct_number_of_columns() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo 'home/viking/spam.txt'
+            | path parse
+            | pivot
+            | get Column0
+            | length
+        "#
+    ));
+
+    #[cfg(windows)]
+    let expected = "4";
+    #[cfg(not(windows))]
+    let expected = "3";
+
+    assert_eq!(actual.out, expected);
+}

crates/nu-command/tests/commands/path/split.rs

@@ -0,0 +1,48 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn splits_empty_path() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo '' | path split
+        "#
+    ));
+
+    assert_eq!(actual.out, "");
+}
+
+#[test]
+fn splits_correctly_single_path() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            'home/viking/spam.txt'
+            | path split
+            | last
+        "#
+    ));
+
+    assert_eq!(actual.out, "spam.txt");
+}
+
+#[test]
+fn splits_correctly_with_column_path() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo [
+                [home, barn];
+
+                ['home/viking/spam.txt', 'barn/cow/moo.png']
+                ['home/viking/eggs.txt', 'barn/goat/cheese.png']
+            ]
+            | path split -c [ home barn ]
+            | get barn
+            | flatten
+            | length
+        "#
+    ));
+
+    assert_eq!(actual.out, "6");
+}

crates/nu-command/tests/commands/path/type_.rs

@@ -0,0 +1,58 @@
+use nu_test_support::fs::Stub::EmptyFile;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn returns_type_of_missing_file() {
+    let actual = nu!(
+        cwd: "tests", pipeline(
+        r#"
+            echo "spam.txt" 
+            | path type
+        "#
+    ));
+
+    assert_eq!(actual.out, "");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn returns_type_of_existing_file() {
+    Playground::setup("path_expand_1", |dirs, sandbox| {
+        sandbox
+            .within("menu")
+            .with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                echo "menu" 
+                | path type
+            "#
+        ));
+
+        assert_eq!(actual.out, "dir");
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn returns_type_of_existing_directory() {
+    Playground::setup("path_expand_1", |dirs, sandbox| {
+        sandbox
+            .within("menu")
+            .with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                echo "menu/spam.txt" 
+                | path type
+            "#
+        ));
+
+        assert_eq!(actual.out, "file");
+    })
+}

crates/nu-command/tests/commands/prepend.rs

@@ -0,0 +1,29 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn adds_a_row_to_the_beginning() {
+    Playground::setup("prepend_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "los_tres_caballeros.txt",
+            r#"
+                Andrés N. Robalino
+                Jonathan Turner
+                Yehuda Katz
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open los_tres_caballeros.txt
+                | lines
+                | prepend "pollo loco"
+                | nth 0
+                "#
+        ));
+
+        assert_eq!(actual.out, "pollo loco");
+    })
+}

crates/nu-command/tests/commands/random/bool.rs

@@ -0,0 +1,16 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn generates_a_bool() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        random bool
+        "#
+    ));
+
+    let output = actual.out;
+    let is_boolean_output = output == "true" || output == "false";
+
+    assert!(is_boolean_output);
+}

crates/nu-command/tests/commands/random/chars.rs

@@ -0,0 +1,14 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn generates_chars_of_specified_length() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        random chars -l 15 | size | get chars
+        "#
+    ));
+
+    let result = actual.out;
+    assert_eq!(result, "15");
+}

crates/nu-command/tests/commands/random/decimal.rs

@@ -0,0 +1,43 @@
+use nu_test_support::{nu, pipeline};
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn generates_an_decimal() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        random decimal 42..43
+        "#
+    ));
+
+    assert!(actual.out.contains("42") || actual.out.contains("43"));
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn generates_55() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        random decimal 55..55
+        "#
+    ));
+
+    assert!(actual.out.contains("55"));
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn generates_0() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        random decimal ..<1
+        "#
+    ));
+
+    assert!(actual.out.contains('0'));
+}

crates/nu-command/tests/commands/random/dice.rs

@@ -0,0 +1,13 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn rolls_4_roll() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        random dice -d 4 -s 10 | length
+        "#
+    ));
+
+    assert_eq!(actual.out, "4");
+}

crates/nu-command/tests/commands/random/integer.rs

@@ -0,0 +1,39 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn generates_an_integer() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        random integer 42..43
+        "#
+    ));
+
+    assert!(actual.out.contains("42") || actual.out.contains("43"));
+}
+
+#[test]
+fn generates_55() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        random integer 55..55
+        "#
+    ));
+
+    assert!(actual.out.contains("55"));
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn generates_0() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        random integer ..<1
+        "#
+    ));
+
+    assert!(actual.out.contains('0'));
+}

crates/nu-command/tests/commands/random/mod.rs

@@ -0,0 +1,7 @@
+mod bool;
+mod chars;
+mod decimal;
+mod dice;
+mod integer;
+#[cfg(feature = "uuid_crate")]
+mod uuid;

crates/nu-command/tests/commands/random/uuid.rs

@@ -0,0 +1,16 @@
+use nu_test_support::{nu, pipeline};
+use uuid_crate::Uuid;
+
+#[test]
+fn generates_valid_uuid4() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        random uuid
+        "#
+    ));
+
+    let result = Uuid::parse_str(actual.out.as_str());
+
+    assert!(result.is_ok());
+}

crates/nu-command/tests/commands/range.rs

@@ -0,0 +1,68 @@
+use nu_test_support::fs::Stub::EmptyFile;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn selects_a_row() {
+    Playground::setup("range_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("notes.txt"), EmptyFile("tests.txt")]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | sort-by name
+                | range 0..0
+                | get name
+            "#
+        ));
+
+        assert_eq!(actual.out, "notes.txt");
+    });
+}
+
+#[test]
+fn selects_some_rows() {
+    Playground::setup("range_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("notes.txt"),
+            EmptyFile("tests.txt"),
+            EmptyFile("persons.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | get name
+                | range 1..2
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "2");
+    });
+}
+
+#[test]
+fn negative_indices() {
+    Playground::setup("range_test_negative_indices", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("notes.txt"),
+            EmptyFile("tests.txt"),
+            EmptyFile("persons.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | get name
+                | range (-1..)
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "1");
+    });
+}

crates/nu-command/tests/commands/reduce.rs

@@ -0,0 +1,138 @@
+use nu_test_support::{nu, pipeline};
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn reduce_table_column() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo "[{month:2,total:30}, {month:3,total:10}, {month:4,total:3}, {month:5,total:60}]"
+        | from json
+        | get total
+        | reduce -f 20 { $it.item + (math eval $"($item.acc)^1.05")}
+        | into string -d 1
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "180.6");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn reduce_table_column_with_path() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        [{month:2,total:30}, {month:3,total:10}, {month:4,total:3}, {month:5,total:60}]
+        | reduce -f 20 { $it.item.total + (math eval $"($item.acc)^1.05")}
+        | into string -d 1
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "180.6");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn reduce_rows_example() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        [[a,b]; [1,2] [3,4]]
+        | reduce -f 1.6 { $it.acc * ($it.item.a | into int) + ($it.item.b | into int) }
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "14.8");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn reduce_numbered_example() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo one longest three bar
+        | reduce -n { if ($it.item.item | str length) > ($it.acc.item | str length) {echo $it.item} else {echo $it.acc}}
+        | get index
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "1");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn reduce_numbered_integer_addition_example() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo [1 2 3 4]
+        | reduce -n { $it.acc.item + $it.item.item }
+        | get item
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "10");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn folding_with_tables() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo [10 20 30 40]
+        | reduce -f [] {
+            with-env [value $it.item] {
+              echo $acc | append (10 * ($env.value | into int))
+            }
+          }
+        | math sum
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "1000");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn error_reduce_fold_type_mismatch() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo a b c | reduce -f 0 { $it.acc + $it.item }
+        "#
+        )
+    );
+
+    assert!(actual.err.contains("mismatch"));
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn error_reduce_empty() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        reduce { $it.$acc + $it.item }
+        "#
+        )
+    );
+
+    assert!(actual.err.contains("needs input"));
+}

crates/nu-command/tests/commands/rename.rs

@@ -0,0 +1,91 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn changes_the_column_name() {
+    Playground::setup("rename_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "los_cuatro_mosqueteros.txt",
+            r#"
+                Andrés N. Robalino
+                Jonathan Turner
+                Yehuda Katz
+                Jason Gedge
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open los_cuatro_mosqueteros.txt
+                | lines
+                | wrap name
+                | rename mosqueteros
+                | get mosqueteros
+                | length
+                "#
+        ));
+
+        assert_eq!(actual.out, "4");
+    })
+}
+
+#[test]
+fn keeps_remaining_original_names_given_less_new_names_than_total_original_names() {
+    Playground::setup("rename_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "los_cuatro_mosqueteros.txt",
+            r#"
+                Andrés N. Robalino
+                Jonathan Turner
+                Yehuda Katz
+                Jason Gedge
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open los_cuatro_mosqueteros.txt
+                | lines
+                | wrap name
+                | default hit "arepa!"
+                | rename mosqueteros
+                | get hit
+                | length
+                "#
+        ));
+
+        assert_eq!(actual.out, "4");
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn errors_if_no_columns_present() {
+    Playground::setup("rename_test_3", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "los_cuatro_mosqueteros.txt",
+            r#"
+                Andrés N. Robalino
+                Jonathan Turner
+                Yehuda Katz
+                Jason Gedge
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open los_cuatro_mosqueteros.txt
+                | lines
+                | rename mosqueteros
+                "#
+        ));
+
+        assert!(actual.err.contains("no column names available"));
+        assert!(actual.err.contains("can't rename"));
+    })
+}

crates/nu-command/tests/commands/reverse.rs

@@ -0,0 +1,11 @@
+use nu_test_support::nu;
+
+#[test]
+fn can_get_reverse_first() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats",
+        "ls | sort-by name | reverse | first 1 | get name | str trim "
+    );
+
+    assert_eq!(actual.out, "utf16.ini");
+}

crates/nu-command/tests/commands/rm.rs

@@ -0,0 +1,334 @@
+use nu_test_support::fs::{files_exist_at, Stub::EmptyFile};
+use nu_test_support::nu;
+use nu_test_support::playground::Playground;
+
+#[test]
+fn removes_a_file() {
+    Playground::setup("rm_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("i_will_be_deleted.txt")]);
+
+        nu!(
+            cwd: dirs.root(),
+            "rm rm_test_1/i_will_be_deleted.txt"
+        );
+
+        let path = dirs.test().join("i_will_be_deleted.txt");
+
+        assert!(!path.exists());
+    })
+}
+
+#[test]
+fn removes_files_with_wildcard() {
+    Playground::setup("rm_test_2", |dirs, sandbox| {
+        sandbox
+            .within("src")
+            .with_files(vec![
+                EmptyFile("cli.rs"),
+                EmptyFile("lib.rs"),
+                EmptyFile("prelude.rs"),
+            ])
+            .within("src/parser")
+            .with_files(vec![EmptyFile("parse.rs"), EmptyFile("parser.rs")])
+            .within("src/parser/parse")
+            .with_files(vec![EmptyFile("token_tree.rs")])
+            .within("src/parser/hir")
+            .with_files(vec![
+                EmptyFile("baseline_parse.rs"),
+                EmptyFile("baseline_parse_tokens.rs"),
+            ]);
+
+        nu!(
+            cwd: dirs.test(),
+            r#"rm "src/*/*/*.rs""#
+        );
+
+        assert!(!files_exist_at(
+            vec![
+                "src/parser/parse/token_tree.rs",
+                "src/parser/hir/baseline_parse.rs",
+                "src/parser/hir/baseline_parse_tokens.rs"
+            ],
+            dirs.test()
+        ));
+
+        assert_eq!(
+            Playground::glob_vec(&format!("{}/src/*/*/*.rs", dirs.test().display())),
+            Vec::<std::path::PathBuf>::new()
+        );
+    })
+}
+
+#[test]
+fn removes_deeply_nested_directories_with_wildcard_and_recursive_flag() {
+    Playground::setup("rm_test_3", |dirs, sandbox| {
+        sandbox
+            .within("src")
+            .with_files(vec![
+                EmptyFile("cli.rs"),
+                EmptyFile("lib.rs"),
+                EmptyFile("prelude.rs"),
+            ])
+            .within("src/parser")
+            .with_files(vec![EmptyFile("parse.rs"), EmptyFile("parser.rs")])
+            .within("src/parser/parse")
+            .with_files(vec![EmptyFile("token_tree.rs")])
+            .within("src/parser/hir")
+            .with_files(vec![
+                EmptyFile("baseline_parse.rs"),
+                EmptyFile("baseline_parse_tokens.rs"),
+            ]);
+
+        nu!(
+            cwd: dirs.test(),
+            "rm -r src/*"
+        );
+
+        assert!(!files_exist_at(
+            vec!["src/parser/parse", "src/parser/hir"],
+            dirs.test()
+        ));
+    })
+}
+
+#[test]
+fn removes_directory_contents_without_recursive_flag_if_empty() {
+    Playground::setup("rm_test_4", |dirs, _| {
+        nu!(
+            cwd: dirs.root(),
+            "rm rm_test_4"
+        );
+
+        assert!(!dirs.test().exists());
+    })
+}
+
+#[test]
+fn removes_directory_contents_with_recursive_flag() {
+    Playground::setup("rm_test_5", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("yehuda.txt"),
+            EmptyFile("jonathan.txt"),
+            EmptyFile("andres.txt"),
+        ]);
+
+        nu!(
+            cwd: dirs.root(),
+            "rm rm_test_5 --recursive"
+        );
+
+        assert!(!dirs.test().exists());
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn errors_if_attempting_to_delete_a_directory_with_content_without_recursive_flag() {
+    Playground::setup("rm_test_6", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("some_empty_file.txt")]);
+        let actual = nu!(
+            cwd: dirs.root(),
+            "rm rm_test_6"
+        );
+
+        assert!(dirs.test().exists());
+        assert!(actual.err.contains("cannot remove non-empty directory"));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn errors_if_attempting_to_delete_single_dot_as_argument() {
+    Playground::setup("rm_test_7", |dirs, _| {
+        let actual = nu!(
+            cwd: dirs.root(),
+            "rm ."
+        );
+
+        assert!(actual.err.contains("cannot remove any parent directory"));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn errors_if_attempting_to_delete_two_dot_as_argument() {
+    Playground::setup("rm_test_8", |dirs, _| {
+        let actual = nu!(
+            cwd: dirs.root(),
+            "rm .."
+        );
+
+        assert!(actual.err.contains("cannot remove any parent directory"));
+    })
+}
+
+#[test]
+fn removes_multiple_directories() {
+    Playground::setup("rm_test_9", |dirs, sandbox| {
+        sandbox
+            .within("src")
+            .with_files(vec![EmptyFile("a.rs"), EmptyFile("b.rs")])
+            .within("src/cli")
+            .with_files(vec![EmptyFile("c.rs"), EmptyFile("d.rs")])
+            .within("test")
+            .with_files(vec![EmptyFile("a_test.rs"), EmptyFile("b_test.rs")]);
+
+        nu!(
+            cwd: dirs.test(),
+            "rm src test --recursive"
+        );
+
+        assert_eq!(
+            Playground::glob_vec(&format!("{}/*", dirs.test().display())),
+            Vec::<std::path::PathBuf>::new()
+        );
+    })
+}
+
+#[test]
+fn removes_multiple_files() {
+    Playground::setup("rm_test_10", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("yehuda.txt"),
+            EmptyFile("jonathan.txt"),
+            EmptyFile("andres.txt"),
+        ]);
+
+        nu!(
+            cwd: dirs.test(),
+            "rm yehuda.txt jonathan.txt andres.txt"
+        );
+
+        assert_eq!(
+            Playground::glob_vec(&format!("{}/*", dirs.test().display())),
+            Vec::<std::path::PathBuf>::new()
+        );
+    })
+}
+
+#[test]
+fn removes_multiple_files_with_asterisks() {
+    Playground::setup("rm_test_11", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("yehuda.txt"),
+            EmptyFile("jonathan.txt"),
+            EmptyFile("andres.toml"),
+        ]);
+
+        nu!(
+            cwd: dirs.test(),
+            "rm *.txt *.toml"
+        );
+
+        assert_eq!(
+            Playground::glob_vec(&format!("{}/*", dirs.test().display())),
+            Vec::<std::path::PathBuf>::new()
+        );
+    })
+}
+
+#[test]
+fn allows_doubly_specified_file() {
+    Playground::setup("rm_test_12", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("yehuda.txt"), EmptyFile("jonathan.toml")]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "rm *.txt yehuda* *.toml"
+        );
+
+        assert_eq!(
+            Playground::glob_vec(&format!("{}/*", dirs.test().display())),
+            Vec::<std::path::PathBuf>::new()
+        );
+        assert!(!actual.out.contains("error"))
+    })
+}
+
+#[test]
+fn remove_files_from_two_parents_up_using_multiple_dots_and_glob() {
+    Playground::setup("rm_test_13", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("yehuda.txt"),
+            EmptyFile("jonathan.txt"),
+            EmptyFile("kevin.txt"),
+        ]);
+
+        sandbox.within("foo").mkdir("bar");
+
+        nu!(
+            cwd: dirs.test().join("foo/bar"),
+            "rm .../*.txt"
+        );
+
+        assert!(!files_exist_at(
+            vec!["yehuda.txt", "jonathan.txt", "kevin.txt"],
+            dirs.test()
+        ));
+    })
+}
+
+#[test]
+fn no_errors_if_attempting_to_delete_non_existent_file_with_f_flag() {
+    Playground::setup("rm_test_14", |dirs, _| {
+        let actual = nu!(
+            cwd: dirs.root(),
+            "rm -f non_existent_file.txt"
+        );
+
+        assert!(!actual.err.contains("no valid path"));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn rm_wildcard_keeps_dotfiles() {
+    Playground::setup("rm_test_15", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("foo"), EmptyFile(".bar")]);
+
+        nu!(
+            cwd: dirs.test(),
+            r#"rm *"#
+        );
+
+        assert!(!files_exist_at(vec!["foo"], dirs.test()));
+        assert!(files_exist_at(vec![".bar"], dirs.test()));
+    })
+}
+
+#[test]
+fn rm_wildcard_leading_dot_deletes_dotfiles() {
+    Playground::setup("rm_test_16", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("foo"), EmptyFile(".bar")]);
+
+        nu!(
+            cwd: dirs.test(),
+            r#"rm .*"#
+        );
+
+        assert!(files_exist_at(vec!["foo"], dirs.test()));
+        assert!(!files_exist_at(vec![".bar"], dirs.test()));
+    })
+}
+
+#[test]
+fn removes_files_with_case_sensitive_glob_matches_by_default() {
+    Playground::setup("glob_test", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("A0"), EmptyFile("a1")]);
+
+        nu!(
+            cwd: dirs.root(),
+            "rm glob_test/A*"
+        );
+
+        let deleted_path = dirs.test().join("A0");
+        let skipped_path = dirs.test().join("a1");
+
+        assert!(!deleted_path.exists());
+        assert!(skipped_path.exists());
+    })
+}

crates/nu-command/tests/commands/roll.rs

@@ -0,0 +1,178 @@
+use nu_test_support::{nu, pipeline};
+
+mod rows {
+    use super::*;
+
+    fn table() -> String {
+        pipeline(
+            r#"
+            echo [
+                [service, status];
+            
+                [ruby,      DOWN] 
+                [db,        DOWN] 
+                [nud,       DOWN] 
+                [expected,  HERE]
+            ]"#,
+        )
+    }
+
+    // FIXME: jt: needs more work
+    #[ignore]
+    #[test]
+    fn roll_down_by_default() {
+        let actual = nu!(
+        cwd: ".",
+        format!("{} | {}", table(), pipeline(r#"
+            roll
+            | first
+            | get status
+        "#)));
+
+        assert_eq!(actual.out, "HERE");
+    }
+
+    // FIXME: jt: needs more work
+    #[ignore]
+    #[test]
+    fn can_roll_up() {
+        let actual = nu!(
+        cwd: ".",
+        format!("{} | {}", table(), pipeline(r#"
+            roll up 3
+            | first
+            | get status
+        "#)));
+
+        assert_eq!(actual.out, "HERE");
+    }
+}
+
+mod columns {
+    use super::*;
+
+    fn table() -> String {
+        pipeline(
+            r#"
+            echo [
+                [commit_author, origin,      stars];
+            
+                [     "Andres",     EC, amarillito] 
+                [     "Darren",     US,      black] 
+                [   "Jonathan",     US,      black] 
+                [     "Yehuda",     US,      black]
+                [      "Jason",     CA,       gold]
+            ]"#,
+        )
+    }
+
+    // FIXME: jt: needs more work
+    #[ignore]
+    #[test]
+    fn roll_left_by_default() {
+        let actual = nu!(
+        cwd: ".",
+        format!("{} | {}", table(), pipeline(r#"
+            roll column
+            | get
+            | str collect "-"
+        "#)));
+
+        assert_eq!(actual.out, "origin-stars-commit_author");
+    }
+
+    // FIXME: jt: needs more work
+    #[ignore]
+    #[test]
+    fn can_roll_in_the_opposite_direction() {
+        let actual = nu!(
+        cwd: ".",
+        format!("{} | {}", table(), pipeline(r#"
+            roll column 2 --opposite
+            | get
+            | str collect "-"
+        "#)));
+
+        assert_eq!(actual.out, "origin-stars-commit_author");
+    }
+
+    struct ThirtieTwo<'a>(usize, &'a str);
+
+    // FIXME: jt: needs more work
+    #[ignore]
+    #[test]
+    fn can_roll_the_cells_only_keeping_the_header_names() {
+        let four_bitstring = bitstring_to_nu_row_pipeline("00000100");
+        let expected_value = ThirtieTwo(32, "bit1-bit2-bit3-bit4-bit5-bit6-bit7-bit8");
+
+        let actual = nu!(
+            cwd: ".",
+            format!("{} | roll column 3 --opposite --cells-only | get | str collect '-' ", four_bitstring)
+        );
+
+        assert_eq!(actual.out, expected_value.1);
+    }
+
+    // FIXME: jt: needs more work
+    #[ignore]
+    #[test]
+    fn four_in_bitstring_left_shifted_with_three_bits_should_be_32_in_decimal() {
+        let four_bitstring = "00000100";
+        let expected_value = ThirtieTwo(32, "00100000");
+
+        assert_eq!(
+            shift_three_bits_to_the_left_to_bitstring(four_bitstring),
+            expected_value.0.to_string()
+        );
+    }
+
+    fn shift_three_bits_to_the_left_to_bitstring(bits: &str) -> String {
+        // this pipeline takes the bitstring and outputs a nu row literal
+        // for example the number 4 in bitstring:
+        //
+        //  input: 00000100
+        //
+        // output:
+        //  [
+        //   [Column1, Column2, Column3, Column4, Column5, Column6, Column7, Column8];
+        //   [      0,       0,       0,       0,       0,       1,       0,       0]
+        //  ]
+        //
+        let bitstring_as_nu_row_pipeline = bitstring_to_nu_row_pipeline(bits);
+
+        // this pipeline takes the nu bitstring row literal, computes it's
+        // decimal value.
+        let nu_row_literal_bitstring_to_decimal_value_pipeline = pipeline(
+            r#"
+            pivot bit --ignore-titles
+            | get bit
+            | reverse
+            | each --numbered {
+                $it.item * (2 ** $it.index)
+            }
+            | math sum
+        "#,
+        );
+
+        nu!(
+            cwd: ".",
+            format!("{} | roll column 3 | {}", bitstring_as_nu_row_pipeline, nu_row_literal_bitstring_to_decimal_value_pipeline)
+        ).out
+    }
+
+    fn bitstring_to_nu_row_pipeline(bits: &str) -> String {
+        format!(
+            "echo '{}' | {}",
+            bits,
+            pipeline(
+                r#"
+            split chars
+            | each { into int }
+            | rotate counter-clockwise _
+            | reject _
+            | rename bit1 bit2 bit3 bit4 bit5 bit6 bit7 bit8
+        "#
+            )
+        )
+    }
+}

crates/nu-command/tests/commands/rotate.rs

@@ -0,0 +1,85 @@
+use nu_test_support::{nu, pipeline};
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn counter_clockwise() {
+    let table = pipeline(
+        r#"
+        echo [
+            [col1, col2, EXPECTED];
+          
+            [---, "|||",      XX1]
+            [---, "|||",      XX2]
+            [---, "|||",      XX3]
+        ]
+    "#,
+    );
+
+    let expected = nu!(cwd: ".", pipeline(
+        r#"
+        echo [
+            [  Column0, Column1, Column2, Column3];
+
+            [ EXPECTED,    XX1,      XX2,     XX3]
+            [     col2,  "|||",    "|||",   "|||"]
+            [     col1,    ---,      ---,     ---]
+        ]
+        | where Column0 == EXPECTED
+        | get Column1 Column2 Column3
+        | str collect "-"
+        "#,
+    ));
+
+    let actual = nu!(
+        cwd: ".",
+        format!("{} | {}", table, pipeline(r#"
+            rotate counter-clockwise
+            | where Column0 == EXPECTED
+            | get Column1 Column2 Column3
+            | str collect "-"
+        "#)));
+
+    assert_eq!(actual.out, expected.out);
+}
+
+#[test]
+fn clockwise() {
+    let table = pipeline(
+        r#"
+        echo [
+            [col1,  col2, EXPECTED];
+          
+            [ ---, "|||",      XX1]
+            [ ---, "|||",      XX2]
+            [ ---, "|||",      XX3]
+        ]
+    "#,
+    );
+
+    let expected = nu!(cwd: ".", pipeline(
+        r#"
+        echo [
+            [ Column0, Column1, Column2,  Column3];
+
+            [     ---,     ---,     ---,     col1]
+            [   "|||",   "|||",   "|||",     col2]
+            [     XX3,     XX2,     XX1, EXPECTED]
+        ]
+        | where Column3 == EXPECTED
+        | get Column0 Column1 Column2
+        | str collect "-"
+        "#,
+    ));
+
+    let actual = nu!(
+        cwd: ".",
+        format!("{} | {}", table, pipeline(r#"
+            rotate
+            | where Column3 == EXPECTED
+            | get Column0 Column1 Column2
+            | str collect "-"
+        "#)));
+
+    assert_eq!(actual.out, expected.out);
+}

crates/nu-command/tests/commands/save.rs

@@ -0,0 +1,69 @@
+use nu_test_support::fs::{file_contents, Stub::FileWithContent};
+use nu_test_support::nu;
+use nu_test_support::playground::Playground;
+
+#[test]
+fn figures_out_intelligently_where_to_write_out_with_metadata() {
+    Playground::setup("save_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "cargo_sample.toml",
+            r#"
+                [package]
+                name = "nu"
+                version = "0.1.1"
+                authors = ["Yehuda Katz <wycats@gmail.com>"]
+                description = "A shell for the GitHub era"
+                license = "ISC"
+                edition = "2018"
+            "#,
+        )]);
+
+        let subject_file = dirs.test().join("cargo_sample.toml");
+
+        nu!(
+            cwd: dirs.root(),
+            "open save_test_1/cargo_sample.toml | save"
+        );
+
+        let actual = file_contents(&subject_file);
+        assert!(actual.contains("0.1.1"));
+    })
+}
+
+#[test]
+fn writes_out_csv() {
+    Playground::setup("save_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![]);
+
+        let expected_file = dirs.test().join("cargo_sample.csv");
+
+        nu!(
+            cwd: dirs.root(),
+            r#"echo [[name, version, description, license, edition]; [nu, "0.14", "A new type of shell", "MIT", "2018"]] | save save_test_2/cargo_sample.csv"#,
+        );
+
+        let actual = file_contents(expected_file);
+        println!("{}", actual);
+        assert!(actual.contains("nu,0.14,A new type of shell,MIT,2018"));
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn save_append_will_create_file_if_not_exists() {
+    Playground::setup("save_test_3", |dirs, sandbox| {
+        sandbox.with_files(vec![]);
+
+        let expected_file = dirs.test().join("new-file.txt");
+
+        nu!(
+            cwd: dirs.root(),
+            r#"echo hello | save --raw --append save_test_3/new-file.txt"#,
+        );
+
+        let actual = file_contents(expected_file);
+        println!("{}", actual);
+        assert!(actual == "hello");
+    })
+}

crates/nu-command/tests/commands/select.rs

@@ -0,0 +1,128 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn regular_columns() {
+    let actual = nu!(cwd: ".", pipeline(
+        r#"
+            echo [
+                [first_name, last_name, rusty_at, type];
+
+                [Andrés Robalino 10/11/2013 A]
+                [Jonathan Turner 10/12/2013 B]
+                [Yehuda Katz 10/11/2013 A]
+            ]
+            | select rusty_at last_name
+            | nth 0
+            | get last_name
+        "#
+    ));
+
+    assert_eq!(actual.out, "Robalino");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn complex_nested_columns() {
+    Playground::setup("select_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "los_tres_caballeros.json",
+            r#"
+                {
+                    "nu": {
+                        "committers": [
+                            {"name": "Andrés N. Robalino"},
+                            {"name": "Jonathan Turner"},
+                            {"name": "Yehuda Katz"}
+                        ],
+                        "releases": [
+                            {"version": "0.2"}
+                            {"version": "0.8"},
+                            {"version": "0.9999999"}
+                        ],
+                        "0xATYKARNU": [
+                            ["Th", "e", " "],
+                            ["BIG", " ", "UnO"],
+                            ["punto", "cero"]
+                        ]
+                    }
+                }
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open los_tres_caballeros.json
+                | select nu."0xATYKARNU" nu.committers.name nu.releases.version
+                | where nu_releases_version > "0.8"
+                | get nu_releases_version
+            "#
+        ));
+
+        assert_eq!(actual.out, "0.9999999");
+    })
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn allows_if_given_unknown_column_name_is_missing() {
+    let actual = nu!(cwd: ".", pipeline(
+        r#"
+            echo [
+                [first_name, last_name, rusty_at, type];
+
+                [Andrés Robalino 10/11/2013 A]
+                [Jonathan Turner 10/12/2013 B]
+                [Yehuda Katz 10/11/2013 A]
+            ]
+            | select rrusty_at first_name
+            | length
+        "#
+    ));
+
+    assert_eq!(actual.out, "3");
+}
+
+#[test]
+fn column_names_with_spaces() {
+    let actual = nu!(cwd: ".", pipeline(
+        r#"
+            echo [
+                ["first name", "last name"];
+
+                [Andrés Robalino]
+                [Andrés Jnth]
+            ]
+            | select "last name"
+            | get "last name"
+            | str collect " "
+        "#
+    ));
+
+    assert_eq!(actual.out, "Robalino Jnth");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn ignores_duplicate_columns_selected() {
+    let actual = nu!(cwd: ".", pipeline(
+        r#"
+            echo [
+                ["first name", "last name"];
+
+                [Andrés Robalino]
+                [Andrés Jnth]
+            ]
+            | select "first name" "last name" "first name"
+            | get
+            | str collect " "
+        "#
+    ));
+
+    assert_eq!(actual.out, "first name last name");
+}

crates/nu-command/tests/commands/semicolon.rs

@@ -0,0 +1,29 @@
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn semicolon_allows_lhs_to_complete() {
+    Playground::setup("create_test_1", |dirs, _sandbox| {
+        let actual = nu!(
+            cwd: dirs.test(),
+            "touch i_will_be_created_semi.txt; echo done"
+        );
+
+        let path = dirs.test().join("i_will_be_created_semi.txt");
+
+        assert!(path.exists());
+        assert_eq!(actual.out, "done");
+    })
+}
+
+#[test]
+fn semicolon_lhs_error_stops_processing() {
+    let actual = nu!(
+    cwd: "tests/fixtures/formats", pipeline(
+    r#"
+        where 1 1; echo done
+    "#
+    ));
+
+    assert!(!actual.out.contains("done"));
+}

crates/nu-command/tests/commands/skip/mod.rs

@@ -0,0 +1,2 @@
+mod until;
+mod while_;

crates/nu-command/tests/commands/skip/until.rs

@@ -0,0 +1,51 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn condition_is_met() {
+    Playground::setup("skip_until_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "caballeros.txt",
+            r#"
+                CHICKEN SUMMARY                        report date: April 29th, 2020
+                --------------------------------------------------------------------
+                Chicken Collection,29/04/2020,30/04/2020,31/04/2020
+                Yellow Chickens,,,
+                Andrés,0,0,1
+                Jonathan,0,0,1
+                Jason,0,0,1
+                Yehuda,0,0,1
+                Blue Chickens,,,
+                Andrés,0,0,1
+                Jonathan,0,0,1
+                Jason,0,0,1
+                Yehuda,0,0,2
+                Red Chickens,,,
+                Andrés,0,0,1
+                Jonathan,0,0,1
+                Jason,0,0,1
+                Yehuda,0,0,3
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open --raw ./caballeros.txt 
+                | lines 
+                | skip 2 
+                | str trim
+                | str collect (char nl) 
+                | from csv
+                | skip until "Chicken Collection" == "Red Chickens"
+                | skip 1
+                | into int "31/04/2020"
+                | get "31/04/2020"
+                | math sum
+                "#
+        ));
+
+        assert_eq!(actual.out, "6");
+    })
+}

crates/nu-command/tests/commands/skip/while_.rs

@@ -0,0 +1,51 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn condition_is_met() {
+    Playground::setup("skip_while_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "caballeros.txt",
+            r#"
+                CHICKEN SUMMARY                        report date: April 29th, 2020
+                --------------------------------------------------------------------
+                Chicken Collection,29/04/2020,30/04/2020,31/04/2020
+                Yellow Chickens,,,
+                Andrés,0,0,1
+                Jonathan,0,0,1
+                Jason,0,0,1
+                Yehuda,0,0,1
+                Blue Chickens,,,
+                Andrés,0,0,1
+                Jonathan,0,0,1
+                Jason,0,0,1
+                Yehuda,0,0,2
+                Red Chickens,,,
+                Andrés,0,0,1
+                Jonathan,0,0,1
+                Jason,0,0,1
+                Yehuda,0,0,3
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open --raw caballeros.txt
+                | lines 
+                | skip 2 
+                | str trim
+                | str collect (char nl) 
+                | from csv
+                | skip while "Chicken Collection" != "Red Chickens"
+                | skip 1
+                | into int "31/04/2020"
+                | get "31/04/2020"
+                | math sum
+                "#
+        ));
+
+        assert_eq!(actual.out, "6");
+    })
+}

crates/nu-command/tests/commands/sort_by.rs

@@ -0,0 +1,160 @@
+use nu_test_support::{nu, pipeline};
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn by_column() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open cargo_sample.toml --raw
+            | lines
+            | skip 1
+            | first 4
+            | split column "="
+            | sort-by Column1
+            | skip 1
+            | first 1
+            | get Column1
+            | str trim
+        "#
+    ));
+
+    assert_eq!(actual.out, "description");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn by_invalid_column() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open cargo_sample.toml --raw
+            | lines
+            | skip 1
+            | first 4
+            | split column "="
+            | sort-by ColumnThatDoesNotExist
+            | skip 1
+            | first 1
+            | get Column1
+            | str trim
+        "#
+    ));
+
+    assert!(actual.err.contains("Can not find column to sort by"));
+    assert!(actual.err.contains("invalid column"));
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn by_invalid_types() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open cargo_sample.toml --raw
+            | echo [1 "foo"]
+            | sort-by
+        "#
+    ));
+
+    assert!(actual.err.contains("Not all values can be compared"));
+    assert!(actual
+        .err
+        .contains("Unable to sort values, as \"integer\" cannot compare against \"string\""));
+}
+
+#[test]
+fn sort_primitive_values() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open cargo_sample.toml --raw
+            | lines
+            | skip 1
+            | first 6
+            | sort-by
+            | first 1
+        "#
+    ));
+
+    assert_eq!(actual.out, "authors = [\"The Nu Project Contributors\"]");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn ls_sort_by_name_sensitive() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open sample-ls-output.json
+            | sort-by name
+            | select name
+            | to json --raw
+        "#
+    ));
+
+    let json_output = r#"[{"name":"B.txt"},{"name":"C"},{"name":"a.txt"}]"#;
+
+    assert_eq!(actual.out, json_output);
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn ls_sort_by_name_insensitive() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open sample-ls-output.json
+            | sort-by -i name
+            | select name
+            | to json --raw
+        "#
+    ));
+
+    let json_output = r#"[{"name":"a.txt"},{"name":"B.txt"},{"name":"C"}]"#;
+
+    assert_eq!(actual.out, json_output);
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn ls_sort_by_type_name_sensitive() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open sample-ls-output.json
+            | sort-by type name
+            | select name type
+            | to json --raw
+        "#
+    ));
+
+    let json_output = r#"[{"name":"C","type":"Dir"},{"name":"B.txt","type":"File"},{"name":"a.txt","type":"File"}]"#;
+
+    assert_eq!(actual.out, json_output);
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn ls_sort_by_type_name_insensitive() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            open sample-ls-output.json
+            | sort-by -i type name
+            | select name type
+            | to json --raw
+        "#
+    ));
+
+    let json_output = r#"[{"name":"C","type":"Dir"},{"name":"a.txt","type":"File"},{"name":"B.txt","type":"File"}]"#;
+
+    assert_eq!(actual.out, json_output);
+}

crates/nu-command/tests/commands/source.rs

@@ -0,0 +1,153 @@
+use nu_test_support::fs::{AbsolutePath, DisplayPath, Stub::FileWithContent};
+use nu_test_support::nu;
+use nu_test_support::pipeline;
+use nu_test_support::playground::Playground;
+
+#[should_panic]
+#[test]
+fn sources_also_files_under_custom_lib_dirs_path() {
+    Playground::setup("source_test_1", |dirs, nu| {
+        let file = AbsolutePath::new(dirs.test().join("config.toml"));
+        let library_path = AbsolutePath::new(dirs.test().join("lib"));
+
+        nu.with_config(&file);
+        nu.with_files(vec![FileWithContent(
+            "config.toml",
+            &format!(
+                r#"
+                lib_dirs = ["{}"]
+                skip_welcome_message = true
+            "#,
+                library_path.display_path()
+            ),
+        )]);
+
+        nu.within("lib").with_files(vec![FileWithContent(
+            "my_library.nu",
+            r#"
+                source my_library/main.nu
+            "#,
+        )]);
+        nu.within("lib/my_library").with_files(vec![FileWithContent(
+            "main.nu",
+            r#"
+            def hello [] {
+                echo "hello nu"
+            }
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: ".", pipeline(
+            r#"
+                source my_library.nu ;
+
+                hello
+        "#
+        ));
+
+        assert_eq!(actual.out, "hello nu");
+    })
+}
+
+fn try_source_foo_with_double_quotes_in(testdir: &str, playdir: &str) {
+    Playground::setup(playdir, |dirs, sandbox| {
+        let testdir = String::from(testdir);
+        let mut foo_file = testdir.clone();
+        foo_file.push_str("/foo.nu");
+
+        sandbox.mkdir(&testdir);
+        sandbox.with_files(vec![FileWithContent(&foo_file, "echo foo")]);
+
+        let cmd = String::from("source ") + r#"""# + &foo_file + r#"""#;
+
+        let actual = nu!(cwd: dirs.test(), &cmd);
+
+        assert_eq!(actual.out, "foo");
+    });
+}
+
+fn try_source_foo_with_single_quotes_in(testdir: &str, playdir: &str) {
+    Playground::setup(playdir, |dirs, sandbox| {
+        let testdir = String::from(testdir);
+        let mut foo_file = testdir.clone();
+        foo_file.push_str("/foo.nu");
+
+        sandbox.mkdir(&testdir);
+        sandbox.with_files(vec![FileWithContent(&foo_file, "echo foo")]);
+
+        let cmd = String::from("source ") + r#"'"# + &foo_file + r#"'"#;
+
+        let actual = nu!(cwd: dirs.test(), &cmd);
+
+        assert_eq!(actual.out, "foo");
+    });
+}
+
+fn try_source_foo_without_quotes_in(testdir: &str, playdir: &str) {
+    Playground::setup(playdir, |dirs, sandbox| {
+        let testdir = String::from(testdir);
+        let mut foo_file = testdir.clone();
+        foo_file.push_str("/foo.nu");
+
+        sandbox.mkdir(&testdir);
+        sandbox.with_files(vec![FileWithContent(&foo_file, "echo foo")]);
+
+        let cmd = String::from("source ") + &foo_file;
+
+        let actual = nu!(cwd: dirs.test(), &cmd);
+
+        assert_eq!(actual.out, "foo");
+    });
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn sources_unicode_file_in_normal_dir() {
+    try_source_foo_with_single_quotes_in("foo", "source_test_1");
+    try_source_foo_with_double_quotes_in("foo", "source_test_2");
+    try_source_foo_without_quotes_in("foo", "source_test_3");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn sources_unicode_file_in_unicode_dir_without_spaces_1() {
+    try_source_foo_with_single_quotes_in("🚒", "source_test_4");
+    try_source_foo_with_double_quotes_in("🚒", "source_test_5");
+    try_source_foo_without_quotes_in("🚒", "source_test_6");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[cfg(not(windows))] // ':' is not allowed in Windows paths
+#[test]
+fn sources_unicode_file_in_unicode_dir_without_spaces_2() {
+    try_source_foo_with_single_quotes_in(":fire_engine:", "source_test_7");
+    try_source_foo_with_double_quotes_in(":fire_engine:", "source_test_8");
+    try_source_foo_without_quotes_in(":fire_engine:", "source_test_9");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[test]
+fn sources_unicode_file_in_unicode_dir_with_spaces_1() {
+    try_source_foo_with_single_quotes_in("e-$ èрт🚒♞中片-j", "source_test_8");
+    try_source_foo_with_double_quotes_in("e-$ èрт🚒♞中片-j", "source_test_9");
+}
+
+// FIXME: jt: needs more work
+#[ignore]
+#[cfg(not(windows))] // ':' is not allowed in Windows paths
+#[test]
+fn sources_unicode_file_in_unicode_dir_with_spaces_2() {
+    try_source_foo_with_single_quotes_in("e-$ èрт:fire_engine:♞中片-j", "source_test_10");
+    try_source_foo_with_double_quotes_in("e-$ èрт:fire_engine:♞中片-j", "source_test_11");
+}
+
+#[ignore]
+#[test]
+fn sources_unicode_file_in_non_utf8_dir() {
+    // How do I create non-UTF-8 path???
+}

crates/nu-command/tests/commands/split_by.rs

@@ -0,0 +1,54 @@
+use nu_test_support::fs::Stub::{EmptyFile, FileWithContentToBeTrimmed};
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn splits() {
+    Playground::setup("split_by_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "los_tres_caballeros.csv",
+            r#"
+                first_name,last_name,rusty_at,type
+                Andrés,Robalino,10/11/2013,A
+                Jonathan,Turner,10/12/2013,B
+                Yehuda,Katz,10/11/2013,A
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open los_tres_caballeros.csv
+                | group-by rusty_at
+                | split-by type
+                | get A."10/11/2013"
+                | length
+            "#
+        ));
+
+        assert_eq!(actual.out, "2");
+    })
+}
+
+#[test]
+fn errors_if_no_table_given_as_input() {
+    Playground::setup("split_by_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![
+            EmptyFile("los.txt"),
+            EmptyFile("tres.txt"),
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                ls
+                | get name
+                | split-by type
+            "#
+        ));
+
+        assert!(actual.err.contains("requires a table"));
+    })
+}

crates/nu-command/tests/commands/split_column.rs

@@ -0,0 +1,28 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn to_column() {
+    Playground::setup("split_column_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "sample.txt",
+            r#"
+                importer,shipper,tariff_item,name,origin
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open sample.txt
+                | lines
+                | str trim
+                | split column ","
+                | get Column2
+            "#
+        ));
+
+        assert!(actual.out.contains("shipper"));
+    })
+}

crates/nu-command/tests/commands/split_row.rs

@@ -0,0 +1,28 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn to_row() {
+    Playground::setup("split_row_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "sample.txt",
+            r#"
+                importer,shipper,tariff_item,name,origin
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open sample.txt
+                | lines
+                | str trim
+                | split row ","
+                | length
+            "#
+        ));
+
+        assert!(actual.out.contains('5'));
+    })
+}

crates/nu-command/tests/commands/str_/collect.rs

@@ -0,0 +1,53 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn test_1() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo 1..5 | into string | str collect
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "12345");
+}
+
+#[test]
+fn test_2() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo [a b c d] | str collect "<sep>"
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "a<sep>b<sep>c<sep>d");
+}
+
+#[test]
+fn construct_a_path() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo [sample txt] | str collect "."
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "sample.txt");
+}
+
+#[test]
+fn sum_one_to_four() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        1..4 | each { $it } | into string | str collect "+" | math eval
+        "#
+        )
+    );
+
+    assert!(actual.out.contains("10"));
+}

crates/nu-command/tests/commands/str_/into_string.rs

@@ -0,0 +1,158 @@
+use nu_test_support::playground::{Dirs, Playground};
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn from_range() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo 1..5 | into string | to json
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "[\"1\",\"2\",\"3\",\"4\",\"5\"]");
+}
+
+#[test]
+fn from_number() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo 5 | into string
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "5");
+}
+
+#[test]
+fn from_decimal() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo 1.5 | into string
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "1.5");
+}
+
+#[test]
+fn from_boolean() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo $true | into string
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "true");
+}
+
+#[test]
+fn from_string() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo "one" | into string
+        "#
+        )
+    );
+
+    assert_eq!(actual.out, "one");
+}
+
+#[test]
+fn from_filename() {
+    Playground::setup("from_filename", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "sample.toml",
+            r#"
+                [dependency]
+                name = "nu"
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "ls sample.toml | get name | into string"
+        );
+
+        assert_eq!(actual.out, "sample.toml");
+    })
+}
+
+#[test]
+fn from_filesize() {
+    Playground::setup("from_filesize", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "sample.toml",
+            r#"
+                [dependency]
+                name = "nu"
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "ls sample.toml | get size | into string"
+        );
+
+        assert_eq!(actual.out, "25 B");
+    })
+}
+
+#[test]
+fn from_decimal_correct_trailing_zeros() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        = 1.23000 | into string -d 3
+        "#
+    ));
+
+    assert!(actual.out.contains("1.230"));
+}
+
+#[test]
+fn from_int_decimal_correct_trailing_zeros() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        = 1.00000 | into string -d 3
+        "#
+    ));
+
+    assert!(actual.out.contains("1.000"));
+}
+
+#[test]
+fn from_int_decimal_trim_trailing_zeros() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        = 1.00000 | into string | format "{$it} flat"
+        "#
+    ));
+
+    assert!(actual.out.contains("1 flat")); // "1" would match "1.0"
+}
+
+#[test]
+fn from_table() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo '[{"name": "foo", "weight": 32.377}, {"name": "bar", "weight": 15.2}]'
+        | from json
+        | into string weight -d 2
+        "#
+    ));
+
+    assert!(actual.out.contains("32.38"));
+    assert!(actual.out.contains("15.20"));
+}

crates/nu-command/tests/commands/str_/mod.rs

@@ -0,0 +1,356 @@
+mod collect;
+
+use nu_test_support::fs::Stub::FileWithContent;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn trims() {
+    Playground::setup("str_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                    [dependency]
+                    name = "nu "
+                "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "open sample.toml | str trim dependency.name | get dependency.name"
+        );
+
+        assert_eq!(actual.out, "nu");
+    })
+}
+
+#[test]
+fn error_trim_multiple_chars() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo "does it work now?!" | str trim -c "?!"
+        "#
+        )
+    );
+
+    assert!(actual.err.contains("char"));
+}
+
+#[test]
+fn capitalizes() {
+    Playground::setup("str_test_2", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                    [dependency]
+                    name = "nu"
+                "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "open sample.toml | str capitalize dependency.name | get dependency.name"
+        );
+
+        assert_eq!(actual.out, "Nu");
+    })
+}
+
+#[test]
+fn downcases() {
+    Playground::setup("str_test_3", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                    [dependency]
+                    name = "LIGHT"
+                "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "open sample.toml | str downcase dependency.name | get dependency.name"
+        );
+
+        assert_eq!(actual.out, "light");
+    })
+}
+
+#[test]
+fn upcases() {
+    Playground::setup("str_test_4", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                    [package]
+                    name = "nushell"
+                "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "open sample.toml | str upcase package.name | get package.name"
+        );
+
+        assert_eq!(actual.out, "NUSHELL");
+    })
+}
+
+#[test]
+fn camelcases() {
+    Playground::setup("str_test_3", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                    [dependency]
+                    name = "THIS_IS_A_TEST"
+                "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "open sample.toml | str camel-case dependency.name | get dependency.name"
+        );
+
+        assert_eq!(actual.out, "thisIsATest");
+    })
+}
+
+#[test]
+fn converts_to_int() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            echo '{number_as_string: "1"}'
+            | from json
+            | into int number_as_string
+            | rename number
+            | where number == 1
+            | get number
+
+        "#
+    ));
+
+    assert_eq!(actual.out, "1");
+}
+
+#[test]
+fn converts_to_decimal() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            echo "3.1, 0.0415"
+            | split row ","
+            | into decimal
+            | math sum
+        "#
+    ));
+
+    assert_eq!(actual.out, "3.1415");
+}
+
+#[test]
+fn find_and_replaces() {
+    Playground::setup("str_test_6", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                     [fortune.teller]
+                     phone = "1-800-KATZ"
+                 "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                 open sample.toml
+                 | str find-replace KATZ "5289" fortune.teller.phone
+                 | get fortune.teller.phone
+             "#
+        ));
+
+        assert_eq!(actual.out, "1-800-5289");
+    })
+}
+
+#[test]
+fn find_and_replaces_without_passing_field() {
+    Playground::setup("str_test_7", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                     [fortune.teller]
+                     phone = "1-800-KATZ"
+                 "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                 open sample.toml
+                 | get fortune.teller.phone
+                 | str find-replace KATZ "5289"
+             "#
+        ));
+
+        assert_eq!(actual.out, "1-800-5289");
+    })
+}
+
+#[test]
+fn substrings_the_input() {
+    Playground::setup("str_test_8", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                     [fortune.teller]
+                     phone = "1-800-ROBALINO"
+                 "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                 open sample.toml
+                 | str substring 6,14 fortune.teller.phone
+                 | get fortune.teller.phone
+             "#
+        ));
+
+        assert_eq!(actual.out, "ROBALINO");
+    })
+}
+
+#[test]
+fn substring_errors_if_start_index_is_greater_than_end_index() {
+    Playground::setup("str_test_9", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                     [fortune.teller]
+                     phone = "1-800-ROBALINO"
+                 "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                 open sample.toml
+                 | str substring 6,5 fortune.teller.phone
+             "#
+        ));
+
+        assert!(actual
+            .err
+            .contains("End must be greater than or equal to Start"))
+    })
+}
+
+#[test]
+fn substrings_the_input_and_returns_the_string_if_end_index_exceeds_length() {
+    Playground::setup("str_test_10", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                     [package]
+                     name = "nu-arepas"
+                 "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                 open sample.toml
+                 | str substring 0,999 package.name
+                 | get package.name
+             "#
+        ));
+
+        assert_eq!(actual.out, "nu-arepas");
+    })
+}
+
+#[test]
+fn substrings_the_input_and_returns_blank_if_start_index_exceeds_length() {
+    Playground::setup("str_test_11", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                     [package]
+                     name = "nu-arepas"
+                 "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                 open sample.toml
+                 | str substring 50,999 package.name
+                 | get package.name
+             "#
+        ));
+
+        assert_eq!(actual.out, "");
+    })
+}
+
+#[test]
+fn substrings_the_input_and_treats_start_index_as_zero_if_blank_start_index_given() {
+    Playground::setup("str_test_12", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                     [package]
+                     name = "nu-arepas"
+                 "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                 open sample.toml
+                 | str substring ,2 package.name
+                 | get package.name
+             "#
+        ));
+
+        assert_eq!(actual.out, "nu");
+    })
+}
+
+#[test]
+fn substrings_the_input_and_treats_end_index_as_length_if_blank_end_index_given() {
+    Playground::setup("str_test_13", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContent(
+            "sample.toml",
+            r#"
+                     [package]
+                     name = "nu-arepas"
+                 "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                 open sample.toml
+                 | str substring 3, package.name
+                 | get package.name
+             "#
+        ));
+
+        assert_eq!(actual.out, "arepas");
+    })
+}
+
+#[test]
+fn str_reverse() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        echo "nushell" | str reverse
+        "#
+    ));
+
+    assert!(actual.out.contains("llehsun"));
+}

crates/nu-command/tests/commands/touch.rs

@@ -0,0 +1,31 @@
+use nu_test_support::nu;
+use nu_test_support::playground::Playground;
+
+#[test]
+fn creates_a_file_when_it_doesnt_exist() {
+    Playground::setup("create_test_1", |dirs, _sandbox| {
+        nu!(
+            cwd: dirs.test(),
+            "touch i_will_be_created.txt"
+        );
+
+        let path = dirs.test().join("i_will_be_created.txt");
+        assert!(path.exists());
+    })
+}
+
+#[test]
+fn creates_two_files() {
+    Playground::setup("create_test_2", |dirs, _sandbox| {
+        nu!(
+            cwd: dirs.test(),
+            "touch a b"
+        );
+
+        let path = dirs.test().join("a");
+        assert!(path.exists());
+
+        let path2 = dirs.test().join("b");
+        assert!(path2.exists());
+    })
+}