javascript - 测试一个函数在 promise 解析中被调用

Question

我正在构建一个应用程序，我需要在其中测试回调函数是否已在 promise 解析中调用。

实际上，我有以下代码:

const callbackRender = (httpResponse, response) => {
  if (httpResponse.content.content) response.send(httpResponse.content.content)
  else response.render(httpResponse.content.page)
}

const callback = (injector, route) => {
  return (request, response) => {
    const ctrl = injector.get(route.controller)
    const result = ctrl[route.controllerMethod](new HttpRequest())
    if (result.then) {
      result.then(res => {
        console.log('hey I m in !')
        callbackRender(res, response)
      })
    } else {
      callbackRender(result, response)
    }
  }
}

我需要测试

result.then(res => {
        console.log('hey I m in !')
        callbackRender(res, response)
      })

名副其实。

我使用 mocha 和 chai 编写了这个测试，我总是有 0 次 spy 调用:

it('should call the callback render method when httpResponse is a promise', (done) => {
      const mock = sinon.mock(injector)
      const ctrl = new UserControllerMock()
      const routes = routeParser.parseRoutes()
      mock.expects('get').returns(ctrl)
      const spy = chai.spy(callbackRender)
      callback(injector, routes[3])(request, response)
      setTimeout(() => {
        expect(spy).to.have.been.called.once
        mock.verify()
        mock.restore()
        done()
      }, 0)
    })

注意:如果调用得当，promise resolve 部分中的日志消息，我可以将其显示在屏幕上。

有什么想法吗？

Answer 1

返回您的响应，然后您可以在测试中调用then。

const callback = (injector, route) => {
  return (request, response) => {
    const ctrl = injector.get(route.controller)
    const result = ctrl[route.controllerMethod](new HttpRequest())
    if (result.then) {
      return result.then(res => {
        callbackRender(res, response)
      });
    } else {
      return Promise.resolve(callbackRender(result, response));
    }
  }
}

你的测试:

it('should call the callback render method when httpResponse is a promise', (done) => {
      const mock = sinon.mock(injector)
      const ctrl = new UserControllerMock()
      const routes = routeParser.parseRoutes()
      mock.expects('get').returns(ctrl)
      const spy = chai.spy(callbackRender)
      callback(injector, routes[3])(request, response).then(() => {
          expect(spy).to.have.been.called.once
          mock.verify()
          mock.restore()
          done()
      });
  });

虽然，您似乎没有注入(inject) callbackRender，所以您的 spy 可能仍未被调用。