Move most of the root package into a subcrate. (#1445)

This improves incremental build time when working on what was previously
the root package. For example, previously all plugins would be rebuilt
with a change to `src/commands/classified/external.rs`, but now only
`nu-cli` will have to be rebuilt (and anything that depends on it).

crates/nu-cli/tests/commands/uniq.rs

@@ -0,0 +1,142 @@
+use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn removes_duplicate_rows() {
+    Playground::setup("uniq_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
+                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
+                | uniq
+                | count
+                | echo $it
+            "#
+        ));
+
+        assert_eq!(actual, "3");
+    })
+}
+
+#[test]
+fn uniq_values() {
+    Playground::setup("uniq_test_2", |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
+                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
+                | pick type
+                | uniq
+                | count
+                | echo $it
+            "#
+        ));
+
+        assert_eq!(actual, "2");
+    })
+}
+
+#[test]
+fn nested_json_structures() {
+    Playground::setup("uniq_test_3", |dirs, sandbox| {
+        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+            "nested_json_structures.json",
+            r#"
+            [ 
+                {
+                  "name": "this is duplicated",
+                  "nesting": [ { "a": "a", "b": "b" },
+                               { "c": "c", "d": "d" }
+                  ],
+                  "can_be_ordered_differently": {
+                    "array": [1, 2, 3, 4, 5],
+                    "something": { "else": "works" }
+                  }
+                },
+                {
+                  "can_be_ordered_differently": {
+                    "something": { "else": "works" },
+                    "array": [1, 2, 3, 4, 5]
+                  },
+                  "nesting": [ { "b": "b", "a": "a" },
+                               { "d": "d", "c": "c" }
+                  ],
+                  "name": "this is duplicated"
+                },
+                {
+                  "name": "this is unique",
+                  "nesting": [ { "a": "b", "b": "a" },
+                               { "c": "d", "d": "c" }
+                  ],
+                  "can_be_ordered_differently": {
+                    "array": [],
+                    "something": { "else": "does not work" }
+                  }
+                },
+                {
+                  "name": "this is unique",
+                  "nesting": [ { "a": "a", "b": "b", "c": "c" },
+                               { "d": "d", "e": "e", "f": "f" }
+                  ],
+                  "can_be_ordered_differently": {
+                    "array": [],
+                    "something": { "else": "works" }
+                  }
+                }
+              ]
+            "#,
+        )]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                open nested_json_structures.json
+                | uniq
+                | count
+                | echo $it
+            "#
+        ));
+        assert_eq!(actual, "3");
+    })
+}
+
+#[test]
+fn uniq_when_keys_out_of_order() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            echo '[{"a": "a", "b": [1,2,3]},{"b": [1,2,3], "a": "a"}]'
+            | from-json
+            | uniq
+            | count
+            | echo $it
+        "#
+    ));
+
+    assert_eq!(actual, "1");
+}