def test_version_check_does_not_exist(self):
        """test the version check on an nonexistend branch."""
        output = self.run_command("selfupdate --check selfupdate_test_does_not_exist", exitcode=0)
        self.assertIn("Target: ywangd:selfupdate_test_does_not_exist", output)
        self.assertNotIn("Target: ywangd:master", output)
        self.assertNotIn("Already at latest version", output)
        self.assertNotIn("New version available", output)
        self.assertIn("Error: ", output)
test the version check on an nonexistend branch.
tests/misc/test_selfupdate.py