def test_ls_cwd(self):
        """test 'ls' of data/ sibling dir without specified path."""
        output = self.run_command("ls", exitcode=0)
        self.assertIn("file1.txt", output)
        self.assertIn("file2.txt", output)
        self.assertNotIn(".hidden", output)
test 'ls' of data/ sibling dir without specified path.
tests/ls/test_ls.py