@Test
public void testAuthenticate_oAuth2NotRequireAppEngineUser() throws ServiceUnavailableException {

  when(jwtAuthenticator.authenticate(request)).thenReturn(null);
  when(oauth2Authenticator.authenticate(request)).thenReturn(USER);
  System.setProperty(EnvUtil.ENV_APPENGINE_RUNTIME, "Production");
  attr.set(Attribute.REQUIRE_APPENGINE_USER, false);
  assertEquals(USER, authenticator.authenticate(request));
}