Command tests (#922)

* WIP command tests

* Finish marking todo tests

* update

* update

* Windows cd test ignoring

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);
+}