def test_directory_has_modified_file(self):
        self.modify_file(self.gitrepodir, 'a.txt', 'aaa')

        self.assertTrue(working_directory_dirty(self.gitrepodir))
`FlockerScriptRunner.sys` is `sys` by default.
dataset/ETHPy150Open robmadole/jig/src/jig/gitutils/tests/test_checks.py/TestWorkingDirctoryDirty.test_directory_has_modified_file--crossover with--dataset/ETHPy150Open ClusterHQ/flocker/flocker/common/test/test_script.py/FlockerScriptRunnerInitTests.test_sys_default