Jest Axios 测试在不应该通过的时候通过了

Question

我正在编写一个脚本（见下文）以确保 axios 函数在收到特定状态代码时抛出错误。 然而，我发现即使我使这个测试失败，Jest 仍然说测试通过，即使它在控制台中返回一个错误（见下文）。 为什么 Jest 说这个测试通过了，而实际上它失败了？ 它是否与我试图预期错误有关，因此即使测试失败，jest 仍然收到错误（测试失败）并认为这意味着我得到了预期的结果？ 谢谢。

foo.test.js：

import axios from 'axios';

jest.mock('axios', () => ({
  get: jest.fn(() => Promise.resolve({ data: 'payload' })),
}));

const getData = async (url) => {
  const response = await axios.get(url);
  if (response.status !== 200) {
    return response.text().then((error) => {
      throw new Error(error.message);
    });
  } else {
    return response.data;
  }
};

test('testing that an error is thrown', async () => {
  axios.get.mockImplementation(() =>
    Promise.resolve({
      data: {data: 'payload'},
      status: 400,
      text: () => Promise.resolve(JSON.stringify({message: 'This is an error.'})),
    })
  );

  const expectedError = async () => {
    await getData('sampleUrl');
  };

  // The error should return 'This is an error.' and instead
  // is expecting 'foo', so this test should fail.
  expect(expectedError()).rejects.toThrowError('foo');
});

Answer 1

您需要进行两次更改才能使测试按预期失败。

• 不要将text的解析值字符串化
• await使用rejects的expect

这是一个按预期失败的更新版本：

import axios from 'axios';

jest.mock('axios', () => ({
  get: jest.fn(() => Promise.resolve({ data: 'payload' })),
}));

const getData = async (url) => {
  const response = await axios.get(url);
  if (response.status !== 200) {
    return response.text().then((error) => {
      throw new Error(error.message);
    });
  } else {
    return response.data;
  }
};

test('testing that an error is thrown', async () => {
  axios.get.mockImplementation(() =>
    Promise.resolve({
      data: {data: 'payload'},
      status: 400,
      text: () => Promise.resolve({message: 'This is an error.'}),  // <= don't stringify
    })
  );

  const expectedError = async () => {
    await getData('sampleUrl');
  };

  await expect(expectedError()).rejects.toThrowError('foo');  // <= await
});