Question

我的React Native + Jest + Typescript设置出现问题。

我试图测试thunk / network操作。我创建了一个networkClient函数：

export const networkClient = async (
  apiPath: string,
  method = RequestType.GET,
  body = {},
  authenticate = true,
  appState: IAppState,
  dispatch: Dispatch<any>
) => {
    ... validate/renew token, validate request and stuff...

    const queryParams = {
      method,
      headers: authenticate
        ? helpers.getHeadersWithAuth(tokenToUse)
        : helpers.getBaseHeaders(),
      body: method === RequestType.POST ? body : undefined,
    };
    const fullUri = baseURL + apiPath;

    const result = await fetch(fullUri, queryParams);
    if (result.ok) {
      const json = await result.json();
      console.log(`Result ${result.status} for request to ${fullUri}`);
      return json;
    } else {
      ... handle error codes
    }
  } catch (error) {
    handleNetworkError(error, apiPath);
  }
};

现在，在为上面使用networkClient的操作编写测试时，请求服务器数据如下：

  const uri = `/subscriptions/media` + tokenParam;
  const json = await networkClient(
    uri,
    RequestType.GET,
    undefined,
    true,
    getState(),
    dispatch
  );

我想模拟实现以返回模拟响应pr。测试。

作为文档，我认为可以这样做：

import { RequestType, networkClient} from './path/to/NetworkClient';

并且在测试中：

networkClient = jest.fn(
  (
    apiPath: string,
    method = RequestType.GET,
    body = {},
    authenticate = true,
    appState: IAppState,
    dispatch: Dispatch<any>
  ) => {
    return 'my test json';
  }
);

const store = mockStore(initialState);
return store
      .dispatch(operations.default.getMoreFeedData(false))
      .then(() => {
        expect(store.getActions()).toEqual(expectedActions);
        expect(store.getState().feedData).toEqual(testFeed);
        // fetchMock.restore();
      });

但是没有定义networkClient，ts告诉我

[ts] Cannot assign to 'networkClient' because it is not a variable.

我出错了什么？我一定错过了Jest如何模拟模块以及如何在某个地方提供模拟实现，但我无法在文档和Google / SO上找到它。

非常感谢任何帮助

Answer 1

所以我找到了解决方案

导入不应该是

import { RequestType, networkClient} from './path/to/NetworkClient';

但是应该像这样要求模块：

const network = require('./../../../../networking/NetworkClient');

之后，我可以成功模拟实现并完成测试：

const testFeed = { items: feed, token: 'nextpage' };
network.networkClient = jest.fn(() => {
  return testFeed;
});

我希望它有助于某人

用Jest嘲笑HttpClient

1 个答案: