javascript - 监视函数 sinon 返回的函数

Question

我对 Sinon 有点陌生，在我不仅需要监视一个函数，还需要监视函数返回的函数的情况下遇到了一些麻烦。具体来说，我正在尝试模拟 Azure 存储 SDK 并确保在创建队列服务后，队列服务返回的方法也会被调用。这是示例:

// test.js

// Setup a Sinon sandbox for each test
test.beforeEach(async t => {

    sandbox = Sinon.sandbox.create();
});

// Restore the sandbox after each test
test.afterEach(async t => {

    sandbox.restore();
});

test.only('creates a message in the queue for the payment summary email', async t => {

    // Create a spy on the mock
    const queueServiceSpy = sandbox.spy(AzureStorageMock, 'createQueueService');

    // Replace the library with the mock
    const EmailUtil = Proxyquire('../../lib/email', {
        'azure-storage': AzureStorageMock,
        '@noCallThru': true
    });

    await EmailUtil.sendBusinessPaymentSummary();

    // Expect that the `createQueueService` method was called
    t.true(queueServiceSpy.calledOnce); // true

    // Expect that the `createMessage` method returned by
    // `createQueueService` is called
    t.true(queueServiceSpy.createMessage.calledOnce); // undefined
});

这是模拟:

const Sinon = require('sinon');

module.exports =  {

    createQueueService: () => {

        return {

            createQueueIfNotExists: (queueName) => {

                return Promise.resolve(Sinon.spy());
            },

            createMessage: (queueName, message) => {

                return Promise.resolve(Sinon.spy());
            }
        };
    }
};

我能够确认 queueServiceSpy 被调用了一次，但我无法确定该方法返回的方法是否被调用 (createMessage)。

是否有更好的设置方法，还是我只是遗漏了什么？

谢谢!

Answer 1

您需要做的是 stub 您的服务函数以返回一个 spy ，然后您可以跟踪对其他地方的调用。您可以将其嵌套任意深(尽管我强烈反对这样做)。

类似于:

const cb = sandbox.spy();
const queueServiceSpy = sandbox.stub(AzureStorageMock, 'createQueueService')
    .returns({createMessage() {return cb;}}});

const EmailUtil = Proxyquire('../../lib/email', {
    'azure-storage': AzureStorageMock,
    '@noCallThru': true
});

await EmailUtil.sendBusinessPaymentSummary();

// Expect that the `createQueueService` method was called
t.true(queueServiceSpy.calledOnce); // true

// Expect that the `createMessage` method returned by
// `createQueueService` is called
t.true(cb.calledOnce);