Question

我想用Jest模拟异步函数的catch块中的返回值

这是我正在为其编写单元测试的功能：

  try {
    make some axios request
    }
    return users;
  } catch (err) {
    return new Map();
  }
};

    it('should catch error when query is unsuccessful', async () => {
      axios.get.mockRejectedValue(new Map());
      const res = getUserDataByIds('someUserIds');
      await expect(res).rejects.toThrow();
    });

我从Jest那里得到了错误：

 expect(received).rejects.toEqual()
 Received promise resolved instead of rejected
 Resolved to value: Map {}

我希望测试能够通过，因为我正在模拟一个被拒绝的值。

Answer 1

这是解决方案：

LONG：

index.ts

import axios from 'axios'; export async function getUserDataByIds(ids: string[]) { try { const users = await axios.get('/users'); return users; } catch (err) { return new Map(); } }：

index.spec.ts

覆盖率100％的单元测试结果：

import { getUserDataByIds } from './';
import axios from 'axios';

jest.mock('axios');

describe('getUserDataByIds', () => {
  afterEach(() => {
    jest.resetAllMocks();
  });
  it('should return empty Map when axios.get failed', async () => {
    const getError = new Error('network error');
    axios.get = jest.fn().mockRejectedValue(getError);
    const actualValue = await getUserDataByIds(['1']);
    expect(actualValue).toEqual(new Map());
    expect(axios.get).toBeCalledWith('/users');
  });

  it('should return users', async () => {
    const mockedUsers = [{ userId: 1 }];
    axios.get = jest.fn().mockResolvedValue(mockedUsers);
    const actualValue = await getUserDataByIds(['1']);
    expect(actualValue).toEqual(mockedUsers);
    expect(axios.get).toBeCalledWith('/users');
  });
});

源代码：https://github.com/mrdulin/jest-codelab/tree/master/src/stackoverflow/58273544

如何在玩笑中正确使用axios.get.mockResolvedValue进行异步调用

1 个答案: