nu-path crate refactor (#3730)

* Resolve rebase artifacts

* Remove leftover dependencies on removed feature

* Remove unnecessary 'pub'

* Start taking notes and fooling around

* Split canonicalize to two versions; Add TODOs

One that takes `relative_to` and one that doesn't.
More TODO notes.

* Merge absolutize to and rename resolve_dots

* Add custom absolutize fn and use it in path expand

* Convert a couple of dunce::canonicalize to ours

* Update nu-path description

* Replace all canonicalize with nu-path version

* Remove leftover dunce dependencies

* Fix broken autocd with trailing slash

Trailing slash is preserved *only* in paths that do not contain "." or
"..". This should be fixed in the future to cover all paths but for now
it at least covers basic cases.

* Use dunce::canonicalize for canonicalizing

* Alow cd recovery from non-existent cwd

* Disable removed canonicalize functionality tests

Remove unused import

* Break down nu-path into separate modules

* Remove unused public imports

* Remove abundant cow mapping

* Fix clippy warning

* Reformulate old canonicalize tests to expand_path

They wouldn't work with the new canonicalize.

* Canonicalize also ~ and ndots; Unify path joining

Also, add doc comments in nu_path::expansions.

* Add comment

* Avoid expanding ndots if path is not valid UTF-8

With this change, no lossy path->string conversion should happen in the
nu-path crate.

* Fmt

* Slight expand_tilde refactor; Add doc comments

* Start nu-path integration tests

* Add tests TODO

* Fix docstring typo

* Fix some doc strings

* Add README for nu-path crate

* Add a couple of canonicalize tests

* Add nu-path integration tests

* Add trim trailing slashes tests

* Update nu-path dependency

* Remove unused import

* Regenerate lockfile

crates/nu-path/tests/canonicalize.rs

@@ -0,0 +1,412 @@
+use std::path::Path;
+
+use nu_test_support::fs::Stub::EmptyFile;
+use nu_test_support::playground::Playground;
+
+use nu_path::{canonicalize, canonicalize_with};
+
+#[test]
+fn canonicalize_path() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+
+        let mut spam = dirs.test().clone();
+        spam.push("spam.txt");
+
+        let actual = canonicalize(spam).expect("Failed to canonicalize");
+
+        assert!(actual.ends_with("spam.txt"));
+    });
+}
+
+#[test]
+fn canonicalize_unicode_path() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("🚒.txt")]);
+
+        let mut spam = dirs.test().clone();
+        spam.push("🚒.txt");
+
+        let actual = canonicalize(spam).expect("Failed to canonicalize");
+
+        assert!(actual.ends_with("🚒.txt"));
+    });
+}
+
+#[ignore]
+#[test]
+fn canonicalize_non_utf8_path() {
+    // TODO
+}
+
+#[test]
+fn canonicalize_path_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual = canonicalize_with("spam.txt", dirs.test()).expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn canonicalize_unicode_path_relative_to_unicode_path_with_spaces() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.mkdir("e-$ èрт🚒♞中片-j");
+        sandbox.with_files(vec![EmptyFile("e-$ èрт🚒♞中片-j/🚒.txt")]);
+
+        let mut relative_to = dirs.test().clone();
+        relative_to.push("e-$ èрт🚒♞中片-j");
+
+        let actual = canonicalize_with("🚒.txt", relative_to).expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("e-$ èрт🚒♞中片-j/🚒.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[ignore]
+#[test]
+fn canonicalize_non_utf8_path_relative_to_non_utf8_path_with_spaces() {
+    // TODO
+}
+
+#[test]
+fn canonicalize_absolute_path_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+
+        let mut absolute_path = dirs.test().clone();
+        absolute_path.push("spam.txt");
+
+        let actual = canonicalize_with(&absolute_path, "non/existent/directory")
+            .expect("Failed to canonicalize");
+        let expected = absolute_path;
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn canonicalize_dot() {
+    let actual = canonicalize(".").expect("Failed to canonicalize");
+    let expected = std::env::current_dir().expect("Could not get current directory");
+
+    assert_eq!(actual, expected);
+}
+
+#[test]
+fn canonicalize_many_dots() {
+    let actual = canonicalize("././/.//////./././//.///").expect("Failed to canonicalize");
+    let expected = std::env::current_dir().expect("Could not get current directory");
+
+    assert_eq!(actual, expected);
+}
+
+#[test]
+fn canonicalize_path_with_dot_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual = canonicalize_with("./spam.txt", dirs.test()).expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn canonicalize_path_with_many_dots_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual = canonicalize_with("././/.//////./././//.////spam.txt", dirs.test())
+            .expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn canonicalize_double_dot() {
+    let actual = canonicalize("..").expect("Failed to canonicalize");
+    let cwd = std::env::current_dir().expect("Could not get current directory");
+    let expected = cwd
+        .parent()
+        .expect("Could not get parent of current directory");
+
+    assert_eq!(actual, expected);
+}
+
+#[test]
+fn canonicalize_path_with_double_dot_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.mkdir("foo");
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual =
+            canonicalize_with("foo/../spam.txt", dirs.test()).expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn canonicalize_path_with_many_double_dots_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.mkdir("foo/bar/baz");
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual = canonicalize_with("foo/bar/baz/../../../spam.txt", dirs.test())
+            .expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn canonicalize_ndots() {
+    let actual = canonicalize("...").expect("Failed to canonicalize");
+    let cwd = std::env::current_dir().expect("Could not get current directory");
+    let expected = cwd
+        .parent()
+        .expect("Could not get parent of current directory")
+        .parent()
+        .expect("Could not get parent of a parent of current directory");
+
+    assert_eq!(actual, expected);
+}
+
+#[test]
+fn canonicalize_path_with_3_ndots_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.mkdir("foo/bar");
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual =
+            canonicalize_with("foo/bar/.../spam.txt", dirs.test()).expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn canonicalize_path_with_many_3_ndots_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.mkdir("foo/bar/baz/eggs/sausage/bacon");
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual = canonicalize_with(
+            "foo/bar/baz/eggs/sausage/bacon/.../.../.../spam.txt",
+            dirs.test(),
+        )
+        .expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn canonicalize_path_with_4_ndots_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.mkdir("foo/bar/baz");
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual = canonicalize_with("foo/bar/baz/..../spam.txt", dirs.test())
+            .expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn canonicalize_path_with_many_4_ndots_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.mkdir("foo/bar/baz/eggs/sausage/bacon");
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual = canonicalize_with(
+            "foo/bar/baz/eggs/sausage/bacon/..../..../spam.txt",
+            dirs.test(),
+        )
+        .expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn canonicalize_path_with_way_too_many_dots_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.mkdir("foo/bar/baz/eggs/sausage/bacon/vikings");
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+
+        let mut relative_to = dirs.test().clone();
+        relative_to.push("foo/bar/baz/eggs/sausage/bacon/vikings");
+
+        let actual = canonicalize_with("././..////././...///././.....///spam.txt", relative_to)
+            .expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn canonicalize_unicode_path_with_way_too_many_dots_relative_to_unicode_path_with_spaces() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.mkdir("foo/áčěéí  +šř=é/baz/eggs/e-$ èрт🚒♞中片-j/bacon/öäöä öäöä");
+        sandbox.with_files(vec![EmptyFile("🚒.txt")]);
+
+        let mut relative_to = dirs.test().clone();
+        relative_to.push("foo/áčěéí  +šř=é/baz/eggs/e-$ èрт🚒♞中片-j/bacon/öäöä öäöä");
+
+        let actual = canonicalize_with("././..////././...///././.....///🚒.txt", relative_to)
+            .expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("🚒.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn canonicalize_tilde() {
+    let tilde_path = "~";
+
+    let actual = canonicalize(tilde_path).expect("Failed to canonicalize");
+
+    assert!(actual.is_absolute());
+    assert!(!actual.starts_with("~"));
+}
+
+#[test]
+fn canonicalize_tilde_relative_to() {
+    let tilde_path = "~";
+
+    let actual =
+        canonicalize_with(tilde_path, "non/existent/path").expect("Failed to canonicalize");
+
+    assert!(actual.is_absolute());
+    assert!(!actual.starts_with("~"));
+}
+
+#[cfg(not(target_arch = "wasm32"))]
+#[test]
+fn canonicalize_symlink() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+        sandbox.symlink("spam.txt", "link_to_spam.txt");
+
+        let mut symlink_path = dirs.test().clone();
+        symlink_path.push("link_to_spam.txt");
+
+        let actual = canonicalize(symlink_path).expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[cfg(not(target_arch = "wasm32"))]
+#[test]
+fn canonicalize_symlink_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+        sandbox.symlink("spam.txt", "link_to_spam.txt");
+
+        let actual =
+            canonicalize_with("link_to_spam.txt", dirs.test()).expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[cfg(not(target_arch = "wasm32"))]
+#[cfg(not(windows))] // seems like Windows symlink requires existing file or dir
+#[test]
+fn canonicalize_symlink_loop_relative_to_should_fail() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        // sandbox.with_files(vec![EmptyFile("spam.txt")]);
+        sandbox.symlink("spam.txt", "link_to_spam.txt");
+        sandbox.symlink("link_to_spam.txt", "spam.txt");
+
+        let actual = canonicalize_with("link_to_spam.txt", dirs.test());
+
+        assert!(actual.is_err());
+    });
+}
+
+#[cfg(not(target_arch = "wasm32"))]
+#[test]
+fn canonicalize_nested_symlink_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.with_files(vec![EmptyFile("spam.txt")]);
+        sandbox.symlink("spam.txt", "link_to_spam.txt");
+        sandbox.symlink("link_to_spam.txt", "link_to_link_to_spam.txt");
+
+        let actual = canonicalize_with("link_to_link_to_spam.txt", dirs.test())
+            .expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[cfg(not(target_arch = "wasm32"))]
+#[test]
+fn canonicalize_nested_symlink_within_symlink_dir_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, sandbox| {
+        sandbox.mkdir("foo/bar/baz");
+        sandbox.with_files(vec![EmptyFile("foo/bar/baz/spam.txt")]);
+        sandbox.symlink("foo/bar/baz/spam.txt", "foo/bar/link_to_spam.txt");
+        sandbox.symlink("foo/bar/link_to_spam.txt", "foo/link_to_link_to_spam.txt");
+        sandbox.symlink("foo", "link_to_foo");
+
+        let actual = canonicalize_with("link_to_foo/link_to_link_to_spam.txt", dirs.test())
+            .expect("Failed to canonicalize");
+        let mut expected = dirs.test().clone();
+        expected.push("foo/bar/baz/spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn canonicalize_should_fail() {
+    let path = Path::new("/foo/bar/baz"); // hopefully, this path does not exist
+
+    assert!(canonicalize(path).is_err());
+}
+
+#[test]
+fn canonicalize_with_should_fail() {
+    let relative_to = "/foo";
+    let path = "bar/baz";
+
+    assert!(canonicalize_with(path, relative_to).is_err());
+}

crates/nu-path/tests/expand_path.rs

@@ -0,0 +1,294 @@
+use std::path::PathBuf;
+
+use nu_test_support::playground::Playground;
+
+use nu_path::{expand_path, expand_path_with};
+
+#[test]
+fn expand_path_with_and_without_relative() {
+    let relative_to = "/foo/bar";
+    let path = "../..";
+    let full_path = "/foo/bar/../..";
+
+    assert_eq!(expand_path(full_path), expand_path_with(path, relative_to),);
+}
+
+#[test]
+fn expand_path_with_relative() {
+    let relative_to = "/foo/bar";
+    let path = "../..";
+
+    assert_eq!(PathBuf::from("/"), expand_path_with(path, relative_to),);
+}
+
+#[test]
+fn expand_path_no_change() {
+    let path = "/foo/bar";
+
+    let actual = expand_path(&path);
+
+    assert_eq!(actual, PathBuf::from(path));
+}
+
+#[test]
+fn expand_unicode_path_no_change() {
+    Playground::setup("nu_path_test_1", |dirs, _| {
+        let mut spam = dirs.test().clone();
+        spam.push("🚒.txt");
+
+        let actual = expand_path(spam);
+        let mut expected = dirs.test().clone();
+        expected.push("🚒.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[ignore]
+#[test]
+fn expand_non_utf8_path() {
+    // TODO
+}
+
+#[test]
+fn expand_path_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, _| {
+        let actual = expand_path_with("spam.txt", dirs.test());
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn expand_unicode_path_relative_to_unicode_path_with_spaces() {
+    Playground::setup("nu_path_test_1", |dirs, _| {
+        let mut relative_to = dirs.test().clone();
+        relative_to.push("e-$ èрт🚒♞中片-j");
+
+        let actual = expand_path_with("🚒.txt", relative_to);
+        let mut expected = dirs.test().clone();
+        expected.push("e-$ èрт🚒♞中片-j/🚒.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[ignore]
+#[test]
+fn expand_non_utf8_path_relative_to_non_utf8_path_with_spaces() {
+    // TODO
+}
+
+#[test]
+fn expand_absolute_path_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, _| {
+        let mut absolute_path = dirs.test().clone();
+        absolute_path.push("spam.txt");
+
+        let actual = expand_path_with(&absolute_path, "non/existent/directory");
+        let expected = absolute_path;
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn expand_path_dot() {
+    let actual = expand_path(".");
+    let expected = PathBuf::from(".");
+
+    assert_eq!(actual, expected);
+}
+
+#[test]
+fn expand_path_many_dots() {
+    let actual = expand_path("././/.//////./././//.///");
+    let expected = PathBuf::from("././././././.");
+
+    assert_eq!(actual, expected);
+}
+
+#[test]
+fn expand_path_with_dot_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, _| {
+        let actual = expand_path_with("./spam.txt", dirs.test());
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn expand_path_double_dot() {
+    let actual = expand_path("..");
+    let expected = PathBuf::from("..");
+
+    assert_eq!(actual, expected);
+}
+
+#[test]
+fn expand_path_dot_double_dot() {
+    let actual = expand_path("./..");
+    let expected = PathBuf::from("./..");
+
+    assert_eq!(actual, expected);
+}
+
+#[test]
+fn expand_path_double_dot_dot() {
+    let actual = expand_path("../.");
+    let expected = PathBuf::from("..");
+
+    assert_eq!(actual, expected);
+}
+
+#[test]
+fn expand_path_with_many_dots_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, _| {
+        let actual = expand_path_with("././/.//////./././//.////spam.txt", dirs.test());
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn expand_path_with_double_dot_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, _| {
+        let actual = expand_path_with("foo/../spam.txt", dirs.test());
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn expand_path_with_many_double_dots_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, _| {
+        let actual = expand_path_with("foo/bar/baz/../../../spam.txt", dirs.test());
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn expand_path_ndots() {
+    let actual = expand_path("...");
+    let mut expected = PathBuf::from("..");
+    expected.push("..");
+
+    assert_eq!(actual, expected);
+}
+
+#[test]
+fn expand_normal_path_ndots() {
+    let actual = expand_path("foo/bar/baz/...");
+    let expected = PathBuf::from("foo");
+
+    assert_eq!(actual, expected);
+}
+
+#[test]
+fn expand_path_with_3_ndots_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, _| {
+        let actual = expand_path_with("foo/bar/.../spam.txt", dirs.test());
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn expand_path_with_many_3_ndots_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, _| {
+        let actual = expand_path_with(
+            "foo/bar/baz/eggs/sausage/bacon/.../.../.../spam.txt",
+            dirs.test(),
+        );
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn expand_path_with_4_ndots_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, _| {
+        let actual = expand_path_with("foo/bar/baz/..../spam.txt", dirs.test());
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn expand_path_with_many_4_ndots_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, _| {
+        let actual = expand_path_with(
+            "foo/bar/baz/eggs/sausage/bacon/..../..../spam.txt",
+            dirs.test(),
+        );
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn expand_path_with_way_too_many_dots_relative_to() {
+    Playground::setup("nu_path_test_1", |dirs, _| {
+        let mut relative_to = dirs.test().clone();
+        relative_to.push("foo/bar/baz/eggs/sausage/bacon/vikings");
+
+        let actual = expand_path_with("././..////././...///././.....///spam.txt", relative_to);
+        let mut expected = dirs.test().clone();
+        expected.push("spam.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn expand_unicode_path_with_way_too_many_dots_relative_to_unicode_path_with_spaces() {
+    Playground::setup("nu_path_test_1", |dirs, _| {
+        let mut relative_to = dirs.test().clone();
+        relative_to.push("foo/áčěéí  +šř=é/baz/eggs/e-$ èрт🚒♞中片-j/bacon/öäöä öäöä");
+
+        let actual = expand_path_with("././..////././...///././.....///🚒.txt", relative_to);
+        let mut expected = dirs.test().clone();
+        expected.push("🚒.txt");
+
+        assert_eq!(actual, expected);
+    });
+}
+
+#[test]
+fn expand_path_tilde() {
+    let tilde_path = "~";
+
+    let actual = expand_path(tilde_path);
+
+    assert!(actual.is_absolute());
+    assert!(!actual.starts_with("~"));
+}
+
+#[test]
+fn expand_path_tilde_relative_to() {
+    let tilde_path = "~";
+
+    let actual = expand_path_with(tilde_path, "non/existent/path");
+
+    assert!(actual.is_absolute());
+    assert!(!actual.starts_with("~"));
+}

crates/nu-path/tests/mod.rs

@@ -0,0 +1,3 @@
+mod canonicalize;
+mod expand_path;
+mod util;

crates/nu-path/tests/util.rs

@@ -0,0 +1,45 @@
+use nu_path::trim_trailing_slash;
+use std::path::MAIN_SEPARATOR;
+
+/// Helper function that joins string literals with '/' or '\', based on the host OS
+fn join_path_sep(pieces: &[&str]) -> String {
+    let sep_string = String::from(MAIN_SEPARATOR);
+    pieces.join(&sep_string)
+}
+
+#[test]
+fn trims_trailing_slash_without_trailing_slash() {
+    let path = join_path_sep(&["some", "path"]);
+
+    let actual = trim_trailing_slash(&path);
+
+    assert_eq!(actual, &path)
+}
+
+#[test]
+fn trims_trailing_slash() {
+    let path = join_path_sep(&["some", "path", ""]);
+
+    let actual = trim_trailing_slash(&path);
+    let expected = join_path_sep(&["some", "path"]);
+
+    assert_eq!(actual, &expected)
+}
+
+#[test]
+fn trims_many_trailing_slashes() {
+    let path = join_path_sep(&["some", "path", "", "", "", ""]);
+
+    let actual = trim_trailing_slash(&path);
+    let expected = join_path_sep(&["some", "path"]);
+
+    assert_eq!(actual, &expected)
+}
+
+#[test]
+fn trims_trailing_slash_empty() {
+    let path = String::from(MAIN_SEPARATOR);
+    let actual = trim_trailing_slash(&path);
+
+    assert_eq!(actual, "")
+}