使Jest模拟游戏无法正常工作

Question

I'm having some trouble getting Jest mocking to work.

I'm trying to unit-test a module that has some asynchronous bits in driven by request .

My understanding is currently that:

• I can use the jest.mock() method to mock the entire module.
• I can mock the methods request.get , request.post , etc to make them synchronous and pass particular responses by creating a file inside a __mocks__/ dir.
• Jest will automock modules from the __mocks__/ when they're required/imported.
• I can override the request dependency by loading it after I import the module that imports it into the test file.

I think I'm missing something obvious.

Module I want to test:

// module.js
import request from 'request'

export default function foo() {
  let options = { /* ... */ }
  let callback = function (error, response, body) {
    if (!error && response.statusCode === 200) {
      return /* Response A */
    } else {
      return /* Response B */
    }
  }

  request.post(options, callback);
}

Mocked request module:

// __mock__/request.js

function post(options, callback) {
  callback(undefined, {statusCode: 200})
}

const request = jest.genMockFromModule('request')
request.post = post

export default request;

Module test:

// module.spec.js
import foo from './module'
jest.mock('request')

test('should return response A', function () {
  expect(foo()).toBe(/* Response A */)
});

When I run the module tests,

• the request module does not appear to be mocked, and
• foo does not generate either "Response A" or "Response B"

Anyone know how to mock this to test it properly?

Answer 1

我猜想，在import ...之前移动jest.mock('request')可以帮助您的。