test: add Mac Command Line Tools locator coverage (Fixes #389)

Author: karthiknadig

crates/pet-mac-commandlinetools/src/lib.rs

@@ -12,7 +12,76 @@ use pet_fs::path::resolve_symlink;
 use pet_python_utils::version;
 use pet_python_utils::{env::ResolvedPythonEnv, executable::find_executables};
 use pet_virtualenv::is_virtualenv;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
+
+/// Returns `true` when `name` is `python`, `python3`, or `python3.<minor>`
+/// (where minor is one or more ASCII digits).
+fn is_macos_python_executable_name(name: &str) -> bool {
+    if name == "python" || name == "python3" {
+        return true;
+    }
+    if let Some(rest) = name.strip_prefix("python3.") {
+        return !rest.is_empty() && rest.chars().all(|c| c.is_ascii_digit());
+    }
+    false
+}
+
+/// Returns `true` when `dir` is `"Current"` or a `<major>.<minor>` pair of
+/// ASCII digits (e.g. `"3.9"`).
+fn is_valid_framework_version_dir(dir: &str) -> bool {
+    if dir == "Current" {
+        return true;
+    }
+    match dir.split_once('.') {
+        Some((major, minor)) => {
+            !major.is_empty()
+                && major.chars().all(|c| c.is_ascii_digit())
+                && !minor.is_empty()
+                && minor.chars().all(|c| c.is_ascii_digit())
+        }
+        None => false,
+    }
+}
+
+/// Checks whether the given path (as a pre-computed lossy string) is a valid
+/// Command Line Tools Python executable path.
+///
+/// Accepted shapes:
+///   /Library/Developer/CommandLineTools/usr/bin/<python-exe>
+///   /Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/<ver>/bin/<python-exe>
+fn is_cmdlinetools_python_path(path_str: &str) -> bool {
+    let path = Path::new(path_str);
+
+    let exe_name = match path.file_name().and_then(|n| n.to_str()) {
+        Some(name) => name,
+        None => return false,
+    };
+
+    if !is_macos_python_executable_name(exe_name) {
+        return false;
+    }
+
+    // Shape 1: /Library/Developer/CommandLineTools/usr/bin/<exe>
+    if let Ok(rest) = path.strip_prefix("/Library/Developer/CommandLineTools/usr/bin") {
+        return rest.components().count() == 1;
+    }
+
+    // Shape 2: .../Python3.framework/Versions/<ver>/bin/<exe>
+    if let Ok(rest) = path.strip_prefix(
+        "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions",
+    ) {
+        let components: Vec<_> = rest.components().collect();
+        // Expect exactly 3 components: <version>, "bin", <exe>
+        if components.len() != 3 {
+            return false;
+        }
+        let version_dir = components[0].as_os_str().to_string_lossy();
+        let bin_dir = components[1].as_os_str().to_string_lossy();
+        return is_valid_framework_version_dir(&version_dir) && bin_dir == "bin";
+    }
+
+    false
+}
 
 pub struct MacCmdLineTools {}
 
@@ -45,13 +114,8 @@ impl Locator for MacCmdLineTools {
             return None;
         }
 
-        if !env
-            .executable
-            .starts_with("/Library/Developer/CommandLineTools/usr/bin")
-            && !env.executable.starts_with(
-                "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions",
-            )
-        {
+        let exe_str = env.executable.to_string_lossy();
+        if !is_cmdlinetools_python_path(&exe_str) {
             return None;
         }
 
@@ -246,3 +310,221 @@ impl Locator for MacCmdLineTools {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use pet_core::{python_environment::PythonEnvironmentKind, Locator, LocatorKind};
+
+    // ── locator metadata ──────────────────────────────────────────
+
+    #[test]
+    fn locator_metadata_matches_cmdlinetools_kind() {
+        let loc = MacCmdLineTools::new();
+        assert_eq!(loc.get_kind(), LocatorKind::MacCommandLineTools);
+        assert_eq!(
+            loc.supported_categories(),
+            vec![PythonEnvironmentKind::MacCommandLineTools]
+        );
+    }
+
+    // ── is_macos_python_executable_name ───────────────────────────
+
+    #[test]
+    fn exe_name_accepts_python() {
+        assert!(is_macos_python_executable_name("python"));
+    }
+
+    #[test]
+    fn exe_name_accepts_python3() {
+        assert!(is_macos_python_executable_name("python3"));
+    }
+
+    #[test]
+    fn exe_name_accepts_python3_minor() {
+        assert!(is_macos_python_executable_name("python3.9"));
+        assert!(is_macos_python_executable_name("python3.12"));
+    }
+
+    #[test]
+    fn exe_name_rejects_config_script() {
+        assert!(!is_macos_python_executable_name("python3-config"));
+        assert!(!is_macos_python_executable_name("python3.9-config"));
+    }
+
+    #[test]
+    fn exe_name_rejects_non_python_tools() {
+        assert!(!is_macos_python_executable_name("idle3"));
+        assert!(!is_macos_python_executable_name("pydoc3"));
+        assert!(!is_macos_python_executable_name("pip3"));
+    }
+
+    #[test]
+    fn exe_name_rejects_compact_version() {
+        assert!(!is_macos_python_executable_name("python39"));
+    }
+
+    #[test]
+    fn exe_name_rejects_multi_dot_version() {
+        assert!(!is_macos_python_executable_name("python3.9.1"));
+    }
+
+    #[test]
+    fn exe_name_rejects_trailing_dot() {
+        assert!(!is_macos_python_executable_name("python3."));
+    }
+
+    // ── is_valid_framework_version_dir ────────────────────────────
+
+    #[test]
+    fn version_dir_accepts_current() {
+        assert!(is_valid_framework_version_dir("Current"));
+    }
+
+    #[test]
+    fn version_dir_accepts_major_minor() {
+        assert!(is_valid_framework_version_dir("3.9"));
+        assert!(is_valid_framework_version_dir("3.12"));
+    }
+
+    #[test]
+    fn version_dir_rejects_patch_version() {
+        assert!(!is_valid_framework_version_dir("3.9.1"));
+    }
+
+    #[test]
+    fn version_dir_rejects_bare_major() {
+        assert!(!is_valid_framework_version_dir("3"));
+    }
+
+    #[test]
+    fn version_dir_rejects_empty() {
+        assert!(!is_valid_framework_version_dir(""));
+    }
+
+    #[test]
+    fn version_dir_rejects_dot_only() {
+        assert!(!is_valid_framework_version_dir("."));
+        assert!(!is_valid_framework_version_dir("3."));
+        assert!(!is_valid_framework_version_dir(".9"));
+    }
+
+    // ── is_cmdlinetools_python_path ───────────────────────────────
+
+    #[test]
+    fn cmdlinetools_path_accepts_usr_bin_python3() {
+        assert!(is_cmdlinetools_python_path(
+            "/Library/Developer/CommandLineTools/usr/bin/python3"
+        ));
+    }
+
+    #[test]
+    fn cmdlinetools_path_accepts_usr_bin_python3_versioned() {
+        assert!(is_cmdlinetools_python_path(
+            "/Library/Developer/CommandLineTools/usr/bin/python3.9"
+        ));
+    }
+
+    #[test]
+    fn cmdlinetools_path_accepts_usr_bin_python() {
+        assert!(is_cmdlinetools_python_path(
+            "/Library/Developer/CommandLineTools/usr/bin/python"
+        ));
+    }
+
+    #[test]
+    fn cmdlinetools_path_accepts_framework_versioned_python() {
+        assert!(is_cmdlinetools_python_path(
+            "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.9/bin/python3.9"
+        ));
+    }
+
+    #[test]
+    fn cmdlinetools_path_accepts_framework_current_version() {
+        assert!(is_cmdlinetools_python_path(
+            "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/Current/bin/python3"
+        ));
+    }
+
+    #[test]
+    fn cmdlinetools_path_accepts_framework_bare_python() {
+        assert!(is_cmdlinetools_python_path(
+            "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.9/bin/python"
+        ));
+    }
+
+    #[test]
+    fn cmdlinetools_path_rejects_empty_string() {
+        assert!(!is_cmdlinetools_python_path(""));
+    }
+
+    #[test]
+    fn cmdlinetools_path_rejects_config_script() {
+        assert!(!is_cmdlinetools_python_path(
+            "/Library/Developer/CommandLineTools/usr/bin/python3-config"
+        ));
+        assert!(!is_cmdlinetools_python_path(
+            "/Library/Developer/CommandLineTools/usr/bin/python3.9-config"
+        ));
+    }
+
+    #[test]
+    fn cmdlinetools_path_rejects_non_python_tools() {
+        assert!(!is_cmdlinetools_python_path(
+            "/Library/Developer/CommandLineTools/usr/bin/idle3"
+        ));
+        assert!(!is_cmdlinetools_python_path(
+            "/Library/Developer/CommandLineTools/usr/bin/pydoc3"
+        ));
+    }
+
+    #[test]
+    fn cmdlinetools_path_rejects_framework_invalid_version() {
+        assert!(!is_cmdlinetools_python_path(
+            "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.9.1/bin/python3.9"
+        ));
+    }
+
+    #[test]
+    fn cmdlinetools_path_rejects_framework_nested_path() {
+        assert!(!is_cmdlinetools_python_path(
+            "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.9/bin/subdir/python3.9"
+        ));
+    }
+
+    #[test]
+    fn cmdlinetools_path_rejects_unrelated_path() {
+        assert!(!is_cmdlinetools_python_path("/usr/bin/python3"));
+        assert!(!is_cmdlinetools_python_path("/usr/local/bin/python3"));
+        assert!(!is_cmdlinetools_python_path("/opt/homebrew/bin/python3.11"));
+    }
+
+    #[test]
+    fn cmdlinetools_path_rejects_xcode_path() {
+        assert!(!is_cmdlinetools_python_path(
+            "/Applications/Xcode.app/Contents/Developer/usr/bin/python3"
+        ));
+    }
+
+    #[test]
+    fn cmdlinetools_path_rejects_usr_bin_nested_deeper() {
+        assert!(!is_cmdlinetools_python_path(
+            "/Library/Developer/CommandLineTools/usr/bin/subdir/python3"
+        ));
+    }
+
+    #[test]
+    fn try_from_rejects_cmdlinetools_path_off_macos() {
+        // On non-macOS the locator always returns None regardless of path.
+        if std::env::consts::OS == "macos" {
+            return; // skip on macOS — this test is for other platforms
+        }
+        let loc = MacCmdLineTools::new();
+        let env = PythonEnv::new(
+            PathBuf::from("/Library/Developer/CommandLineTools/usr/bin/python3.9"),
+            None,
+            None,
+        );
+        assert!(loc.try_from(&env).is_none());
+    }
+}