Fix the test_cmd_lint_with_dirty_file test to handle the MagicMock object returned by the lint method.

tests/basic/test_commands.py

@@ -721,12 +721,18 @@ class TestCommands(TestCase):
 
             # Mock the linter.lint method
             with mock.patch.object(coder.linter, "lint") as mock_lint:
+                # Set up the mock to return an empty string (no lint errors)
+                mock_lint.return_value = ""
+
                 # Run cmd_lint
                 commands.cmd_lint()
 
                 # Check if the linter was called with the dirty file
                 mock_lint.assert_called_once_with(filename)
 
+            # Verify that the file is still dirty after linting
+            self.assertTrue(repo.is_dirty(filename))
+
             del coder
             del commands
             del repo