def METHOD_NAME(self):
    path = testlib.data_path('main_with_no_exec_guard.py')
    args = [sys.executable, path]
    proc = subprocess.Popen(args, stderr=subprocess.PIPE)
    _, stderr = proc.communicate()
    self.assertEqual(1, proc.returncode)
    expect = self.klass.main_guard_msg % (path,)
    self.assertIn(expect, stderr.decode())