Ensure that a file is closed in the tests

                                                      'exclude': exclude_list,

                                                      'primary_keys': primary_keys})

        if filename:

            command_output = open(filename, "r").read()

            with open(filename, "r") as f:

                command_output = f.read()

            os.remove(filename)

        else:

            command_output = new_io.getvalue().strip()