Jest TypeScript Error axios_1.default.post.mockImplementatio

Question

请参阅下面的更新：

注意：

我没有使用axios-mock-adapter，除非有人可以指出我可以测试toHaveBeenCalledWith的示例。

我还想避免创建一个̶_̶_̶m̶o̶c̶k̶_̶_̶__mocks__(文件夹，以模拟整个模块。

>错误：

我所有的测试都通过了， 但我仍然收到此类型错误。

TypeError: axios_1.default.post.mockImplementation is not a function
28 | const axiosPost = jest.fn(() => ({ success: true }));
29 | jest.mock('axios');
> 30 | (axios as jest.Mocked<any>).post.mockImplementation(
|                                           ^
31 |   jest.fn().mockImplementation(axiosPost),
32 | );

<小时 />

代码：

文件：__tests__/index.ts

import axios from 'axios';
// ...
// Before Tests
const axiosPost = jest.fn();
jest.mock('axios');
(axios as jest.Mocked<typeof axios>).post.mockImplementation(
jest.fn().mockImplementation(axiosPost),
);
// ...
beforeEach(() => {
jest.clearAllMocks();
});
// Test Performed & Passes
/**
* Validates send email request
*/
test('test - sendEmail - [e-mail], [e-mail], my subject, hello there!', async () => {
// Setup
const from = '[e-mail]';
const to = '[e-mail]';
const subject = 'my subject';
const body = 'hello there!';
const basicAuth = Buffer.from(`api:secret`).toString('base64');
process.env.MAILGUN_API_URL = 'url';
process.env.MAILGUN_DOMAIN = 'domain';
process.env.MAILGUN_SECRET_KEY = 'secret';
// Pre Expectations
expect(formData).not.toHaveBeenCalled();
expect(axiosPost).not.toHaveBeenCalled();
// Init
const result = await sendEmail(from, to, subject, body);
// Post Expectations
// Form Data
expect(formData).toHaveBeenCalledTimes(1);
expect(formDataAppend).toHaveBeenCalledTimes(4);
expect(formDataAppend.mock.calls[0][0]).toEqual('from');
expect(formDataAppend.mock.calls[0][1]).toEqual(from);
expect(formDataAppend.mock.calls[1][0]).toEqual('to');
expect(formDataAppend.mock.calls[1][1]).toEqual(to);
expect(formDataAppend.mock.calls[2][0]).toEqual('subject');
expect(formDataAppend.mock.calls[2][1]).toEqual(subject);
expect(formDataAppend.mock.calls[3][0]).toEqual('html');
expect(formDataAppend.mock.calls[3][1]).toEqual(body);
expect(formDataGetHeaders).toHaveBeenCalledTimes(1);
// Axios
expect(axiosPost).toHaveBeenCalledTimes(1);
expect(axios.post).toHaveBeenCalledWith(
'url/domain/messages',
{ append: formDataAppend, getHeaders: formDataGetHeaders },
{
headers: {
Authorization: `Basic ${basicAuth}`,
'Content-Type': 'multipart/form-data',
},
},
);
expect(result).toStrictEqual({ success: true });
});

<小时 />

更新

根据@estus烧瓶的建议和指示，我修改了代码以将axios模拟为包含post的返回对象，并且不测试jest.fn()而是使用spyOn。

修改文件：__tests__/index.ts

// Mocks
// ========================================================
//  ̶c̶o̶n̶s̶t̶ ̶a̶x̶i̶o̶s̶P̶o̶s̶t̶ ̶=̶ ̶j̶e̶s̶t̶.̶f̶n̶(̶)̶;̶
jest.mock('axios', () => {
return Object.assign(jest.fn(), {
post: jest.fn().mockReturnValue({ success: true }),
});
});
// ...
/**
* Validates send email request
*/
test('test - sendEmail - [e-mail], [e-mail], my subject, hello there!', async () => {
// Setup
const spyOnAxiosPost = jest.spyOn(axios, 'post');
// ...
// Pre Expectations
expect(formData).not.toHaveBeenCalled();
//  ̶e̶x̶p̶e̶c̶t̶(̶a̶x̶i̶o̶s̶P̶o̶s̶t̶)̶.̶n̶o̶t̶.̶t̶o̶H̶a̶v̶e̶B̶e̶e̶n̶C̶a̶l̶l̶e̶d̶(̶)̶;̶
expect(spyOnAxiosPost).not.toBeCalled();
// Init
const result = await sendEmail(from, to, subject, body);
// Post Expectations
// ...
// Axios
//  ̶e̶x̶p̶e̶c̶t̶(̶a̶x̶i̶o̶s̶P̶o̶s̶t̶)̶.̶t̶o̶H̶a̶v̶e̶B̶e̶e̶n̶C̶a̶l̶l̶e̶d̶T̶i̶m̶e̶s̶(̶1̶)̶;̶
expect(spyOnAxiosPost).toBeCalledTimes(1);
// ...
expect(result).toStrictEqual({ success: true });
});

axios

没有完全由Jest自动模拟处理，因为axios是一个函数而不是一个对象，它的方法(如axios.post)被忽略。

对于手动模拟，使用__mocks__(不是__mock__)是可选的。它们可以就地模拟，尽管使用__mocks__进行重用是有意义的：

jest.mock('axios', () => {
return Object.assign(jest.fn(), {
get: jest.fn(),
post: jest.fn(),
...
});
});

axios-mock-adapter和toHaveBeenCalledWith没有问题，因为使用带有自定义适配器的真正 Axios 可以监视方法(但不是axios()函数本身)：

jest.spyOn(axios, 'post');