如何使用API调用测试传奇?

我有一个传奇故事

export function* mysaga(api, action) {
  const response = yield call(api.service, action);
  yield put(NavActions.goTo('Page', { success: response.ok }));
}

调用API并使用返回值导航到另一个屏幕,传递API调用结果( response.ok

it('test', () => {
  // ...

  const gen = mysaga(api, action);
  const step = () => gen.next().value;

  // doesn't actually run the api
  const response = call(api.service, {});

  expect(step()).toMatchObject(response); // ok

  // error, Cannot read property 'ok' of undefined
  expect(step()).toMatchObject(
    put(NavActions.goTo('Page', { success: response.ok }))
  );
});

response 没有定义。