test_wrapper: add test for repo script executable permission

Add a test to verify that the repo launcher script has the
executable bit set, guarding against accidental permission changes.

Change-Id: I314658b57ed174673188fbbc5962d9fdeefac97d
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/569242
Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Carlos Fernandez <carlosfsanz@meta.com>
Reviewed-by: Mike Frysinger <vapier@google.com>
Tested-by: Carlos Fernandez <carlosfsanz@meta.com>

Author: Carlos Fernandez

tests/test_wrapper.py

@@ -106,6 +106,11 @@ def test_python_constraints(self, repo_wrapper: wrapper.Wrapper) -> None:
             >= repo_wrapper.MIN_PYTHON_VERSION_HARD
         )
 
+    def test_repo_script_is_executable(self) -> None:
+        """The repo launcher script should be executable."""
+        repo_path = utils_for_test.THIS_DIR.parent / "repo"
+        assert os.access(repo_path, os.X_OK), f"{repo_path} is not executable"
+
     def test_init_parser(self, repo_wrapper: wrapper.Wrapper) -> None:
         """Make sure 'init' GetParser works."""
         parser = repo_wrapper.GetParser()