使用 Sinon 模拟 require() 的函数

Question

我正在尝试使用Sinon 在测试中模拟request-promise。据我所知，Sinon 模拟对象的方法，而 request-promise 只是返回一个函数。有什么方法可以模拟一个需要的函数吗？

var rp = require('request-promise');
var User = require('../../models/user');

// this works
sinon.stub(User, 'message', function() {});

// This is what I'd like to do to request-promise
sinon.stub(rp, function() {});

我也研究了 mockrequire 和 proxyquire，但我认为它们都遇到了类似的问题。

Answer 1

以下示例应该为您解决问题。通过使用 proxyquire，您可以包装 request-promise 并避免存根 .post、.get、.call 等。在我看来更清洁。

myModule.js:

'use strict';

const rp = require('request-promise');

class MyModule {
  /**
   * Sends a post request to localhost:8080 to create a character.
   */
  static createCharacter(data = {}) {
    const options = {
      method: 'POST',
      uri: 'http://localhost:8080/create-character',
      headers: {'content-type': 'application/json'},
      body: data,
    };
    return rp(options);
  }
}

module.exports = MyModule;

myModule.spec.js:

'use strict';

const proxyquire = require('proxyquire');
const sinon = require('sinon');
const requestPromiseStub = sinon.stub();
const MyModule = proxyquire('./myModule', {'request-promise': requestPromiseStub});

describe('MyModule', () => {
  it('#createCharacter', (done) => {
    // Set the mocked response we want request-promise to respond with
    const responseMock = {id: 2000, firstName: 'Mickey', lastName: 'Mouse'};
    requestPromiseStub.resolves(responseMock);
    MyModule.createCharacter({firstName: 'Mickey', lastName: 'Mouse'})
      .then((response) => {
        // add your expects / asserts here. obviously this doesn't really
        // prove anything since this is the mocked response.
        expect(response).to.have.property('firstName', 'Mickey');
        expect(response).to.have.property('lastName', 'Mouse');
        expect(response).to.have.property('id').and.is.a('number');
        done();
      })
      .catch(done);
  });
});

Answer 2

I found a (sort of) solution here.

基本上，您可以使用 call（apply 也可以）：

// models/user.js
var rp = require('request-promise');

var User = {
    save: function(data) {
        return rp.call(rp, {
            url: ...,
            data: data
        });
    }
}
module.exports = User;



// test/user.js
var rp = require('request-promise');
var User = require('../../models/user');

describe('User', function() {
    it('should check that save passes data through', function() {
        sinon.stub(rp, 'call', function(data) {
            // check data here
        });
        User.save({ foo: 'bar' });
    });
});

它完成了工作，虽然我不喜欢到处都做rp.call，所以我仍然对更好的解决方案抱有希望。