refactor: Improve cross-platform path handling in subtree command tests

tests/basic/test_commands.py

@@ -1184,8 +1184,9 @@ def test_cmd_subtree_relative_path(self):
 
             # Test with relative path
             with mock.patch.object(io, "tool_output") as mock_output:
-                commands.cmd_subtree("dir1/dir2")
-                mock_output.assert_called_with("Changed subtree path to: dir1/dir2")
+                commands.cmd_subtree(os.path.join("dir1", "dir2"))
+                expected_path = os.path.normpath("dir1/dir2")
+                mock_output.assert_called_with(f"Changed subtree path to: {expected_path}")
 
     def test_cmd_subtree_no_repo(self):
         """Test /subtree with no git repo"""
@@ -1219,9 +1220,13 @@ def test_cmd_subtree_outside_repo(self):
             coder = Coder.create(self.GPT35, None, io, repo=repo)
             commands = Commands(io, coder)
 
+            # Create a path that's definitely outside the repo
+            outside_path = os.path.abspath(os.path.join(repo_dir, "..", "outside"))
+            os.makedirs(outside_path, exist_ok=True)
+
             # Try to set path outside repo
             with mock.patch.object(io, "tool_error") as mock_error:
-                commands.cmd_subtree("/tmp")
+                commands.cmd_subtree(outside_path)
                 mock_error.assert_called_with("The path must be within the git repo.")
 
     def test_cmd_test_unbound_local_error(self):