feat(JjLib): JjLib implementation

nix/rust-version.nix

@@ -1,11 +0,0 @@
-{
-  rust-overlay,
-  inputs,
-  system,
-  ...
-}: let
-  overlays = [(import rust-overlay)];
-in rec {
-  pkgs = import inputs.nixpkgs {inherit system overlays;};
-  version = pkgs.rust-bin.stable.latest.default;
-}

nix/shell.nix

@@ -23,22 +23,22 @@ inputs.devenv.lib.mkShell {
         just
       ];
 
-      processes.run.exec = "cargo watch -x run";
+      # processes.run.exec = "cargo watch -x run";
 
-      enterShell = ''
-        echo ""
-        echo "Rust development environment loaded!"
-        echo "Rust version: $(rustc --version)"
-        echo "Cargo version: $(cargo --version)"
-        echo ""
-        echo "Available tools:"
-        echo "  - rust-analyzer (LSP)"
-        echo "  - clippy (linter)"
-        echo "  - rustfmt (formatter)"
-        echo "  - bacon (continuous testing/linting)"
-        echo "  - cargo-deny (dependency checker)"
-        echo "  - cargo-tarpaulin (code coverage)"
-      '';
+      # enterShell = ''
+      #   echo ""
+      #   echo "Rust development environment loaded!"
+      #   echo "Rust version: $(rustc --version)"
+      #   echo "Cargo version: $(cargo --version)"
+      #   echo ""
+      #   echo "Available tools:"
+      #   echo "  - rust-analyzer (LSP)"
+      #   echo "  - clippy (linter)"
+      #   echo "  - rustfmt (formatter)"
+      #   echo "  - bacon (continuous testing/linting)"
+      #   echo "  - cargo-deny (dependency checker)"
+      #   echo "  - cargo-tarpaulin (code coverage)"
+      # '';
     }
   ];
 }

src/error.rs

@@ -16,6 +16,10 @@ pub enum Error {
     JjOperation { context: String },
     #[error("Repository is locked by another process")]
     RepositoryLocked,
+    #[error("Could not get current directory")]
+    FailedGettingCurrentDir,
+    #[error("Could not load Jujutsu configuration")]
+    FailedReadingConfig,
     // Application errors
     #[error("Operation cancelled by user")]
     Cancelled,
@@ -40,3 +44,15 @@ impl From<CommitMessageError> for Error {
         Self::InvalidCommitMessage(value.to_string())
     }
 }
+
+impl From<std::io::Error> for Error {
+    fn from(_value: std::io::Error) -> Self {
+        Self::FailedGettingCurrentDir
+    }
+}
+
+impl From<jj_lib::config::ConfigGetError> for Error {
+    fn from(_: jj_lib::config::ConfigGetError) -> Self {
+        Self::FailedReadingConfig
+    }
+}

src/jj/executor.rs

@@ -0,0 +1,382 @@
+use std::path::Path;
+
+use jj_lib::config::StackedConfig;
+use jj_lib::settings::UserSettings;
+use jj_lib::workspace::{Workspace, default_working_copy_factories};
+use jj_lib::repo::{Repo, StoreFactories};
+
+use crate::error::Error;
+use crate::jj::JjExecutor;
+
+/// JjLib provides jj repository operations using jj-lib
+///
+/// This implementation uses the jj-lib crate directly for all operations,
+/// providing native Rust integration with Jujutsu repositories.
+pub struct JjLib {
+    /// The working directory path for repository operations
+    working_dir: std::path::PathBuf,
+}
+
+impl JjLib {
+    /// Create a new JjLib instance using the current working directory
+    pub fn new() -> Self {
+        Self {
+            working_dir: std::env::current_dir().unwrap_or_default(),
+        }
+    }
+
+    /// Create a new JjLib instance with a specific working directory
+    pub fn with_working_dir(path: impl AsRef<Path>) -> Self {
+        Self {
+            working_dir: path.as_ref().to_path_buf(),
+        }
+    }
+}
+
+impl Default for JjLib {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[async_trait::async_trait]
+impl JjExecutor for JjLib {
+    async fn is_repository(&self) -> Result<bool, Error> {
+        let config = StackedConfig::with_defaults();
+        let settings = UserSettings::from_config(config)?;
+        let store_factories = StoreFactories::default();
+        let wc_factories = default_working_copy_factories();
+        match Workspace::load(&settings, &std::env::current_dir()?, &store_factories, &wc_factories) {
+            Ok(_) => Ok(true),
+            Err(_) => Ok(false)
+        }
+    }
+
+    async fn describe(&self, _message: &str) -> Result<(), Error> {
+        // TODO: T018/T019 - Implement using jj-lib transactions
+        todo!("T018/T019: Implement describe() using jj-lib")
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use assert_fs::prelude::*;
+    use std::process::Command;
+
+    /// Initialize a jj repository in the given directory using `jj git init`
+    fn init_jj_repo(dir: &std::path::Path) -> std::io::Result<()> {
+        let output = Command::new("jj")
+            .args(["git", "init"])
+            .current_dir(dir)
+            .output()?;
+
+        if !output.status.success() {
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::Other,
+                format!(
+                    "jj git init failed: {}",
+                    String::from_utf8_lossy(&output.stderr)
+                ),
+            ));
+        }
+        Ok(())
+    }
+
+    /// Get the current commit description from a jj repository
+    fn get_commit_description(dir: &std::path::Path) -> std::io::Result<String> {
+        let output = Command::new("jj")
+            .args(["log", "-r", "@", "--no-graph", "-T", "description"])
+            .current_dir(dir)
+            .output()?;
+
+        if !output.status.success() {
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::Other,
+                format!(
+                    "jj log failed: {}",
+                    String::from_utf8_lossy(&output.stderr)
+                ),
+            ));
+        }
+        Ok(String::from_utf8_lossy(&output.stdout).trim().to_string())
+    }
+
+    /// Test that is_repository() returns true inside a jj repository
+    ///
+    /// This test:
+    /// 1. Creates a temporary directory
+    /// 2. Initializes a jj repository with `jj git init`
+    /// 3. Verifies is_repository() returns Ok(true)
+    #[tokio::test]
+    async fn is_repository_returns_true_inside_jj_repo() {
+        // Create a temporary directory
+        let temp_dir = assert_fs::TempDir::new().unwrap();
+
+        // Initialize a jj repository
+        init_jj_repo(temp_dir.path()).expect("Failed to init jj repo");
+
+        // Create JjLib pointing to the temp directory
+        let jj_lib = JjLib::with_working_dir(temp_dir.path());
+
+        // Verify is_repository returns true
+        let result = jj_lib.is_repository().await;
+        assert!(result.is_ok(), "Expected Ok, got {:?}", result);
+        assert!(
+            result.unwrap(),
+            "Expected true for directory inside jj repo"
+        );
+    }
+
+    /// Test that is_repository() returns true from a subdirectory of a jj repo
+    ///
+    /// This verifies that jj-lib correctly walks up the directory tree
+    /// to find the repository root.
+    #[tokio::test]
+    async fn is_repository_returns_true_from_subdirectory() {
+        // Create a temporary directory with a subdirectory
+        let temp_dir = assert_fs::TempDir::new().unwrap();
+        let sub_dir = temp_dir.child("subdir/nested");
+        sub_dir.create_dir_all().unwrap();
+
+        // Initialize jj repo at the root
+        init_jj_repo(temp_dir.path()).expect("Failed to init jj repo");
+
+        // Create JjLib pointing to the subdirectory
+        let jj_lib = JjLib::with_working_dir(sub_dir.path());
+
+        // Verify is_repository returns true from subdirectory
+        let result = jj_lib.is_repository().await;
+        assert!(result.is_ok(), "Expected Ok, got {:?}", result);
+        assert!(
+            result.unwrap(),
+            "Expected true for subdirectory inside jj repo"
+        );
+    }
+
+    /// Test that is_repository() returns false outside a jj repository
+    ///
+    /// This test:
+    /// 1. Creates an empty temporary directory (no jj init)
+    /// 2. Verifies is_repository() returns Ok(false)
+    #[tokio::test]
+    async fn is_repository_returns_false_outside_jj_repo() {
+        // Create an empty temporary directory (not a jj repo)
+        let temp_dir = assert_fs::TempDir::new().unwrap();
+
+        // Create JjLib pointing to the temp directory
+        let jj_lib = JjLib::with_working_dir(temp_dir.path());
+
+        // Verify is_repository returns false
+        let result = jj_lib.is_repository().await;
+        assert!(result.is_ok(), "Expected Ok, got {:?}", result);
+        assert!(
+            !result.unwrap(),
+            "Expected false for directory outside jj repo"
+        );
+    }
+
+    /// Test that is_repository() returns false for non-existent directory
+    ///
+    /// This verifies graceful handling of invalid paths
+    #[tokio::test]
+    async fn is_repository_returns_false_for_nonexistent_directory() {
+        // Create a path that doesn't exist
+        let nonexistent = std::path::PathBuf::from("/tmp/jj_cz_nonexistent_test_dir_12345");
+
+        // Make sure it doesn't exist
+        if nonexistent.exists() {
+            std::fs::remove_dir_all(&nonexistent).ok();
+        }
+
+        let jj_lib = JjLib::with_working_dir(&nonexistent);
+
+        // Verify is_repository returns false (not an error)
+        let result = jj_lib.is_repository().await;
+        assert!(result.is_ok(), "Expected Ok, got {:?}", result);
+        assert!(
+            !result.unwrap(),
+            "Expected false for non-existent directory"
+        );
+    }
+
+    /// Test that describe() updates the commit description
+    ///
+    /// This test:
+    /// 1. Creates a temp jj repo
+    /// 2. Calls describe() with a test message
+    /// 3. Verifies the commit description was updated via `jj log`
+    #[tokio::test]
+    async fn describe_updates_commit_description() {
+        // Create a temporary directory and init jj repo
+        let temp_dir = assert_fs::TempDir::new().unwrap();
+        init_jj_repo(temp_dir.path()).expect("Failed to init jj repo");
+
+        // Create JjLib pointing to the temp directory
+        let jj_lib = JjLib::with_working_dir(temp_dir.path());
+
+        // Call describe with a test message
+        let test_message = "feat(scope): add new feature";
+        let result = jj_lib.describe(test_message).await;
+
+        assert!(result.is_ok(), "describe() should succeed, got {:?}", result);
+
+        // Verify the commit description was updated
+        let actual_description =
+            get_commit_description(temp_dir.path()).expect("Failed to get commit description");
+
+        assert_eq!(
+            actual_description, test_message,
+            "Commit description should match the message passed to describe()"
+        );
+    }
+
+    /// Test that describe() handles multiline messages
+    #[tokio::test]
+    async fn describe_handles_multiline_message() {
+        let temp_dir = assert_fs::TempDir::new().unwrap();
+        init_jj_repo(temp_dir.path()).expect("Failed to init jj repo");
+
+        let jj_lib = JjLib::with_working_dir(temp_dir.path());
+
+        let multiline_message = "feat: add feature\n\nThis is the body of the commit.\nIt spans multiple lines.";
+        let result = jj_lib.describe(multiline_message).await;
+
+        assert!(result.is_ok(), "describe() should succeed with multiline message");
+
+        let actual_description = get_commit_description(temp_dir.path()).unwrap();
+        assert_eq!(actual_description, multiline_message);
+    }
+
+    /// Test that describe() handles empty message (clears description)
+    #[tokio::test]
+    async fn describe_handles_empty_message() {
+        let temp_dir = assert_fs::TempDir::new().unwrap();
+        init_jj_repo(temp_dir.path()).expect("Failed to init jj repo");
+
+        let jj_lib = JjLib::with_working_dir(temp_dir.path());
+
+        // First set a description
+        jj_lib
+            .describe("initial message")
+            .await
+            .expect("First describe should succeed");
+
+        // Then clear it with empty message
+        let result = jj_lib.describe("").await;
+        assert!(result.is_ok(), "describe() should succeed with empty message");
+
+        let actual_description = get_commit_description(temp_dir.path()).unwrap();
+        assert_eq!(actual_description, "", "Description should be cleared");
+    }
+
+    /// Test that describe() handles special characters in message
+    #[tokio::test]
+    async fn describe_handles_special_characters() {
+        let temp_dir = assert_fs::TempDir::new().unwrap();
+        init_jj_repo(temp_dir.path()).expect("Failed to init jj repo");
+
+        let jj_lib = JjLib::with_working_dir(temp_dir.path());
+
+        let special_message = "fix: handle \"quotes\" and 'apostrophes' & <brackets>";
+        let result = jj_lib.describe(special_message).await;
+
+        assert!(result.is_ok(), "describe() should handle special characters");
+
+        let actual_description = get_commit_description(temp_dir.path()).unwrap();
+        assert_eq!(actual_description, special_message);
+    }
+
+    /// Test that describe() handles unicode characters
+    #[tokio::test]
+    async fn describe_handles_unicode() {
+        let temp_dir = assert_fs::TempDir::new().unwrap();
+        init_jj_repo(temp_dir.path()).expect("Failed to init jj repo");
+
+        let jj_lib = JjLib::with_working_dir(temp_dir.path());
+
+        let unicode_message = "feat: support émojis 🚀 and ünïcödé characters 中文";
+        let result = jj_lib.describe(unicode_message).await;
+
+        assert!(result.is_ok(), "describe() should handle unicode");
+
+        let actual_description = get_commit_description(temp_dir.path()).unwrap();
+        assert_eq!(actual_description, unicode_message);
+    }
+
+    /// Test that describe() returns NotARepository error outside jj repo
+    #[tokio::test]
+    async fn describe_fails_outside_repository() {
+        // Create an empty temp directory (not a jj repo)
+        let temp_dir = assert_fs::TempDir::new().unwrap();
+
+        let jj_lib = JjLib::with_working_dir(temp_dir.path());
+
+        let result = jj_lib.describe("test message").await;
+
+        assert!(result.is_err(), "describe() should fail outside repository");
+        assert!(
+            matches!(result.unwrap_err(), Error::NotARepository),
+            "Expected NotARepository error"
+        );
+    }
+
+    /// Test that describe() can be called multiple times
+    #[tokio::test]
+    async fn describe_can_be_called_multiple_times() {
+        let temp_dir = assert_fs::TempDir::new().unwrap();
+        init_jj_repo(temp_dir.path()).expect("Failed to init jj repo");
+
+        let jj_lib = JjLib::with_working_dir(temp_dir.path());
+
+        // Call describe multiple times
+        jj_lib.describe("first").await.unwrap();
+        jj_lib.describe("second").await.unwrap();
+        jj_lib.describe("third").await.unwrap();
+
+        // Only the last description should persist
+        let actual_description = get_commit_description(temp_dir.path()).unwrap();
+        assert_eq!(actual_description, "third");
+    }
+
+    /// Test that JjLib::new() creates instance with current directory
+    #[test]
+    fn new_uses_current_directory() {
+        let jj_lib = JjLib::new();
+        let current_dir = std::env::current_dir().unwrap();
+        assert_eq!(jj_lib.working_dir, current_dir);
+    }
+
+    /// Test that JjLib::with_working_dir() uses specified directory
+    #[test]
+    fn with_working_dir_uses_specified_directory() {
+        let custom_path = std::path::PathBuf::from("/tmp/custom");
+        let jj_lib = JjLib::with_working_dir(&custom_path);
+        assert_eq!(jj_lib.working_dir, custom_path);
+    }
+
+    /// Test that JjLib implements Default
+    #[test]
+    fn jjlib_implements_default() {
+        let jj_lib = JjLib::default();
+        let current_dir = std::env::current_dir().unwrap();
+        assert_eq!(jj_lib.working_dir, current_dir);
+    }
+
+    /// Test that JjLib implements JjExecutor trait
+    #[test]
+    fn jjlib_implements_jj_executor() {
+        fn _accepts_executor<E: JjExecutor>(_e: E) {}
+        let jj_lib = JjLib::new();
+        _accepts_executor(jj_lib);
+    }
+
+    /// Test that JjLib is Send + Sync
+    #[test]
+    fn jjlib_is_send_sync() {
+        fn _assert_send<T: Send>() {}
+        fn _assert_sync<T: Sync>() {}
+        _assert_send::<JjLib>();
+        _assert_sync::<JjLib>();
+    }
+}

src/jj/mod.rs

@@ -1 +1,301 @@
+use crate::error::Error;
 
+pub mod executor;
+
+/// Trait for executing jj operations
+///
+/// All methods are async for native jj-lib compatibility.
+#[async_trait::async_trait]
+pub trait JjExecutor: Send + Sync {
+    /// Check if current directory is within a jj repository
+    async fn is_repository(&self) -> Result<bool, Error>;
+
+    /// Set the description of the current change
+    async fn describe(&self, message: &str) -> Result<(), Error>;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// Mock implementation of JjExecutor for testing
+    ///
+    /// This mock allows configuring responses for each method
+    /// and tracks method calls for verification.
+    struct MockJjExecutor {
+        /// Response to return from is_repository()
+        is_repo_response: Result<bool, Error>,
+        /// Response to return from describe()
+        describe_response: Result<(), Error>,
+        /// Track calls to is_repository()
+        is_repo_called: std::sync::atomic::AtomicBool,
+        /// Track calls to describe() with the message passed
+        describe_calls: std::sync::Mutex<Vec<String>>,
+    }
+
+    impl MockJjExecutor {
+        /// Create a new mock with default success responses
+        fn new() -> Self {
+            Self {
+                is_repo_response: Ok(true),
+                describe_response: Ok(()),
+                is_repo_called: std::sync::atomic::AtomicBool::new(false),
+                describe_calls: std::sync::Mutex::new(Vec::new()),
+            }
+        }
+
+        /// Configure is_repository() to return a specific value
+        fn with_is_repo_response(mut self, response: Result<bool, Error>) -> Self {
+            self.is_repo_response = response;
+            self
+        }
+
+        /// Configure describe() to return a specific value
+        fn with_describe_response(mut self, response: Result<(), Error>) -> Self {
+            self.describe_response = response;
+            self
+        }
+
+        /// Check if is_repository() was called
+        fn was_is_repo_called(&self) -> bool {
+            self.is_repo_called.load(std::sync::atomic::Ordering::SeqCst)
+        }
+
+        /// Get all messages passed to describe()
+        fn describe_messages(&self) -> Vec<String> {
+            self.describe_calls.lock().unwrap().clone()
+        }
+    }
+
+    #[async_trait::async_trait]
+    impl JjExecutor for MockJjExecutor {
+        async fn is_repository(&self) -> Result<bool, Error> {
+            self.is_repo_called
+                .store(true, std::sync::atomic::Ordering::SeqCst);
+            match &self.is_repo_response {
+                Ok(v) => Ok(*v),
+                Err(e) => Err(match e {
+                    Error::NotARepository => Error::NotARepository,
+                    Error::JjOperation { context } => Error::JjOperation {
+                        context: context.clone(),
+                    },
+                    Error::RepositoryLocked => Error::RepositoryLocked,
+                    _ => Error::JjOperation {
+                        context: "mock error".to_string(),
+                    },
+                }),
+            }
+        }
+
+        async fn describe(&self, message: &str) -> Result<(), Error> {
+            self.describe_calls
+                .lock()
+                .unwrap()
+                .push(message.to_string());
+            match &self.describe_response {
+                Ok(()) => Ok(()),
+                Err(e) => Err(match e {
+                    Error::NotARepository => Error::NotARepository,
+                    Error::JjOperation { context } => Error::JjOperation {
+                        context: context.clone(),
+                    },
+                    Error::RepositoryLocked => Error::RepositoryLocked,
+                    _ => Error::JjOperation {
+                        context: "mock error".to_string(),
+                    },
+                }),
+            }
+        }
+    }
+
+    /// Test that JjExecutor trait definition compiles
+    ///
+    /// This test verifies:
+    /// - The trait is properly defined with async methods
+    /// - The trait has correct Send + Sync bounds
+    /// - The trait can be used as a type bound
+    #[test]
+    fn trait_definition_compiles() {
+        // If this compiles, the trait definition is valid
+        fn _accepts_executor<E: JjExecutor>(_executor: E) {}
+
+        // Verify trait bounds compile
+        fn _accepts_executor_ref<E: JjExecutor>(_executor: &E) {}
+        fn _accepts_executor_box(_executor: Box<dyn JjExecutor>) {}
+    }
+
+    /// Test that JjExecutor can be used with trait objects
+    ///
+    /// This verifies the trait is object-safe
+    #[test]
+    fn trait_is_object_safe() {
+        // This compiles only if the trait is object-safe
+        let _: Option<Box<dyn JjExecutor>> = None;
+        let _: Option<&dyn JjExecutor> = None;
+    }
+
+    /// Test that JjExecutor requires Send + Sync bounds
+    ///
+    /// This verifies implementors must be thread-safe
+    #[test]
+    fn trait_requires_send_sync() {
+        fn _assert_send<T: Send>() {}
+        fn _assert_sync<T: Sync>() {}
+
+        // MockJjExecutor implements the trait, so it must satisfy Send + Sync
+        _assert_send::<MockJjExecutor>();
+        _assert_sync::<MockJjExecutor>();
+    }
+
+    /// Test that mock can implement JjExecutor trait
+    ///
+    /// This is a compile-time check that the mock properly implements the trait
+    #[test]
+    fn mock_implements_trait() {
+        let mock = MockJjExecutor::new();
+        // If this compiles, the mock implements the trait
+        fn _accepts_executor(_e: impl JjExecutor) {}
+        _accepts_executor(mock);
+    }
+
+    /// Test mock is_repository() returns configured true response
+    #[tokio::test]
+    async fn mock_is_repository_returns_true() {
+        let mock = MockJjExecutor::new().with_is_repo_response(Ok(true));
+        let result = mock.is_repository().await;
+        assert!(result.is_ok());
+        assert!(result.unwrap());
+        assert!(mock.was_is_repo_called());
+    }
+
+    /// Test mock is_repository() returns configured false response
+    #[tokio::test]
+    async fn mock_is_repository_returns_false() {
+        let mock = MockJjExecutor::new().with_is_repo_response(Ok(false));
+        let result = mock.is_repository().await;
+        assert!(result.is_ok());
+        assert!(!result.unwrap());
+    }
+
+    /// Test mock is_repository() returns configured error
+    #[tokio::test]
+    async fn mock_is_repository_returns_error() {
+        let mock = MockJjExecutor::new().with_is_repo_response(Err(Error::NotARepository));
+        let result = mock.is_repository().await;
+        assert!(result.is_err());
+        assert!(matches!(result.unwrap_err(), Error::NotARepository));
+    }
+
+    /// Test mock describe() records the message
+    #[tokio::test]
+    async fn mock_describe_records_message() {
+        let mock = MockJjExecutor::new();
+        let result = mock.describe("test message").await;
+        assert!(result.is_ok());
+        let messages = mock.describe_messages();
+        assert_eq!(messages.len(), 1);
+        assert_eq!(messages[0], "test message");
+    }
+
+    /// Test mock describe() records multiple messages
+    #[tokio::test]
+    async fn mock_describe_records_multiple_messages() {
+        let mock = MockJjExecutor::new();
+        mock.describe("first message").await.unwrap();
+        mock.describe("second message").await.unwrap();
+        let messages = mock.describe_messages();
+        assert_eq!(messages.len(), 2);
+        assert_eq!(messages[0], "first message");
+        assert_eq!(messages[1], "second message");
+    }
+
+    /// Test mock describe() returns configured error
+    #[tokio::test]
+    async fn mock_describe_returns_error() {
+        let mock = MockJjExecutor::new().with_describe_response(Err(Error::RepositoryLocked));
+        let result = mock.describe("test").await;
+        assert!(result.is_err());
+        assert!(matches!(result.unwrap_err(), Error::RepositoryLocked));
+    }
+
+    /// Test mock describe() returns JjOperation error with context
+    #[tokio::test]
+    async fn mock_describe_returns_jj_operation_error() {
+        let mock = MockJjExecutor::new().with_describe_response(Err(Error::JjOperation {
+            context: "transaction failed".to_string(),
+        }));
+        let result = mock.describe("test").await;
+        assert!(result.is_err());
+        match result.unwrap_err() {
+            Error::JjOperation { context } => {
+                assert_eq!(context, "transaction failed");
+            }
+            _ => panic!("Expected JjOperation error"),
+        }
+    }
+
+    /// Test mock can be used through trait object
+    #[tokio::test]
+    async fn mock_works_as_trait_object() {
+        let mock = MockJjExecutor::new();
+        let executor: Box<dyn JjExecutor> = Box::new(mock);
+        let result = executor.is_repository().await;
+        assert!(result.is_ok());
+    }
+
+    /// Test mock can be used through trait reference
+    #[tokio::test]
+    async fn mock_works_as_trait_reference() {
+        let mock = MockJjExecutor::new();
+        let executor: &dyn JjExecutor = &mock;
+        let result = executor.is_repository().await;
+        assert!(result.is_ok());
+    }
+
+    /// Test mock satisfies Send + Sync for concurrent use
+    #[tokio::test]
+    async fn mock_is_thread_safe() {
+        use std::sync::Arc;
+
+        let mock = Arc::new(MockJjExecutor::new());
+        let mock_clone = Arc::clone(&mock);
+
+        // Spawn a task that uses the mock
+        let handle = tokio::spawn(async move { mock_clone.is_repository().await });
+
+        // Use the mock from the main task
+        let result1 = mock.is_repository().await;
+        let result2 = handle.await.unwrap();
+
+        assert!(result1.is_ok());
+        assert!(result2.is_ok());
+    }
+
+    /// Test that empty message can be passed to describe
+    #[tokio::test]
+    async fn mock_describe_accepts_empty_message() {
+        let mock = MockJjExecutor::new();
+        let result = mock.describe("").await;
+        assert!(result.is_ok());
+        assert_eq!(mock.describe_messages()[0], "");
+    }
+
+    /// Test that long message can be passed to describe
+    #[tokio::test]
+    async fn mock_describe_accepts_long_message() {
+        let mock = MockJjExecutor::new();
+        let long_message = "a".repeat(1000);
+        let result = mock.describe(&long_message).await;
+        assert!(result.is_ok());
+        assert_eq!(mock.describe_messages()[0].len(), 1000);
+    }
+
+    /// Test mock tracks is_repository calls
+    #[tokio::test]
+    async fn mock_tracks_is_repository_call() {
+        let mock = MockJjExecutor::new();
+        assert!(!mock.was_is_repo_called());
+        mock.is_repository().await.unwrap();
+        assert!(mock.was_is_repo_called());
+    }
+}