self review

crates/turborepo-scm/src/git.rs

@@ -367,7 +367,8 @@ mod tests {
  };
 
  /// By default `#[test_case]` will run in parallel.
- /// This is a problem for testing things TODO
+ /// This is a problem for testing things like environment variables, which
+ /// are not thread-safe. This lock ensures that these tests run serially.
  static TEST_PARALLELISM_LOCK: OnceLock<Mutex<bool>> = OnceLock::new();
 
  fn setup_repository(
@@ -1145,7 +1146,7 @@ mod tests {
  let _lock = TEST_PARALLELISM_LOCK
  .get_or_init(Mutex::default)
  .lock()
- .unwrap();
+ .expect("failed to acquire TEST_PARALLELISM_LOCK");
 
  // insert any Some values into the environment
  for (key, value) in [
@@ -1158,6 +1159,7 @@ mod tests {
  }
  }
 
+ // note: we must bind here because otherwise the temporary file will be dropped
  let _temp_file = if test_case.GITHUB_EVENT_PATH.is_some() {
  let temp_file = NamedTempFile::new().expect("Failed to create temporary file");
  fs::write(temp_file.path(), test_case.event_json)