javascript - Mocha 测试 Bluebird 驱动的 Node 样式回调

Question

我遇到了通过运行似乎通过的 mocha 来通过测试的麻烦。

测试:

describe('.get()',function() {

    it('should be called once',function() {
        // => Need to spy on this
        var callback = function(err,data) {
            console.log('I am called');
            if (err) {
                console.log('I am logging the error '+err);
            } else {
                console.log('I am logging the data '+data);
            }
        }

        agentMock._response = {body:'something',headers:'headers'};

        // => Start Spying
        var spy = sinon.spy(callback);
        sinon.spy(agentMock,'get');

        baseRequest.get(spy); // refer (a) below

        expect(agentMock.get).to.have.been.calledOnce;
        expect(spy).to.have.been.calledOnce;
        expect(spy).to.have.been.calledWith(null,'data');
    });
});

我想测试 callback 是否被调用。因此，我登录了回调主体，stdout 也表明它正在被调用。

标准输出:

  .get()
    1) should be called once
I am called
I am logging the data something


  0 passing (15ms)
  1 failing

  1) .get() should be called once:
     AssertionError: expected spy to have been called exactly once, but it was called 0 times

详细信息:

(a) baseRequest.get 将数据作为 bluebird promise 返回。这可以通过将 nodeback 传递给 .get 本身或通过在 .get 调用之后链接 .then 来使用.

BaseRequest.prototype.get = function(callback) {
    // inner details

    return invokeandPromisify(request,callback);
}

function invokeandPromisify(request, callback) {
    return new Promise(function(resolve,reject) {
    // Invoke the request
    request.end(function(err,result) {

        // Return the results as a promise
        if (err || result.error) {
            reject(err || result.error);
        } else {
            resolve(result);
        }
    });
    }).nodeify(callback); // to have a node style callback
}

发生这种情况是因为我想要监视的回调被传递给了不同的函数(此处为invokeandPromisify)并且监视是丢失的 ？我只是在解释这个。

问候。

Answer 1

因为 baseRequest#get 返回一个 promise ，我会在 promise 被解决后做出断言。

请看下面的例子:

it('should be called once',function(done) {
    // => Need to spy on this
    var callback = function(err,data) {
        console.log('I am called');
        if (err) {
            console.log('I am logging the error '+err);
        } else {
            console.log('I am logging the data '+data);
        }
    }

    agentMock._response = {body:'something',headers:'headers'};

    // => Start Spying
    var spy = sinon.spy(callback);
    sinon.spy(agentMock,'get');

    baseRequest.get(spy).finally(function() {
      expect(agentMock.get).to.have.been.calledOnce;
      expect(spy).to.have.been.calledOnce;
      expect(spy).to.have.been.calledWith(null,'data');
      done();
    });

});