def test_undo(self):
        """
        Test the undo method.

        @raise AssertionError: If the test fails.
        """
        self.worker.execute(self.raise_temp_command)

        self.assertIn(self.raise_temp_command, self.worker._history)
        self.assertEquals("Temperature lowered by 5 degrees", self.worker.undo())
        self.assertNotIn(self.raise_temp_command, self.worker._history)

        Test the undo method.

        @raise AssertionError: If the test fails.
        
tests/behavioral_tests/test_command.py