如何使用sinon模拟axios.post的异步方法

Question

我正在尝试模拟一个异步函数，该函数在另一个js文件中内部调用n个异步方法。当我嘲笑async函数时，它说"期望post至少被调用一次"。有人能帮忙吗？事先非常感谢。

Controller.js

//all imports done here
var producer= require(./Producer)
const result = async function(req,res,"login"){
const link = req.query.param === team ? '/login' : '/search';
await producer.produce(req,res);
const result = await axios.post(link,req.name,req.dob):
await producer.produce(req,res,"logout");
}

Producer.js

const { EventHubProducerClient } = require("@azure/event-hubs");
const connectionString = "EVENT HUBS NAMESPACE CONNECTION STRING";
const eventHubName = "EVENT HUB NAME";
const produce = async function (req,res,data) =>{
// Create a producer client to send messages to the event hub.
try{
const producer = new EventHubProducerClient(connectionString, eventHubName);
// Prepare a batch of three events.
const batch = await producer.createBatch();
batch.tryAdd({ body: "First event" });
batch.tryAdd({ body: "Second event" });
batch.tryAdd({ body: "Third event" });    
// Send the batch to the event hub.
await producer.sendBatch(batch);
// Close the producer client.
await producer.close();
console.log("A batch of three events have been sent to the event hub");
}catch(error){
throw e;
}
}

controller-test.js

const controller = require(./controller);
describe("execute", =>{
sinon.stub().restore();
const req= {name:"tina", dob:"2-12-2000"};
it("call method to post" =>{
const res = controller.result();
//test fails in the below line
sinon.assert(axios.post,"http://dummyurl/login,req);
});
});

Answer 1

您可以使用sinon.stub(obj, 'method')来存根producer.produce()方法和axios.post()方法。

此外，您应该使用async/await来测试异步代码，这样Mocha就会知道它应该等待这个函数被调用来完成测试。

例如

Controller.js:

const producer = require('./Producer');
const axios = require('axios');
const result = async function (req, res) {
const team = 'thunder';
const link = req.query.param === team ? '/login' : '/search';
await producer.produce(req, res);
const result = await axios.post(link, req.name, req.dob);
await producer.produce(req, res, 'logout');
};
module.exports = { result };

Producer.js

const { EventHubProducerClient } = require('@azure/event-hubs');
const connectionString = 'EVENT HUBS NAMESPACE CONNECTION STRING';
const eventHubName = 'EVENT HUB NAME';
const produce = async (req, res, data) => {
try {
const producer = new EventHubProducerClient(connectionString, eventHubName);
const batch = await producer.createBatch();
batch.tryAdd({ body: 'First event' });
batch.tryAdd({ body: 'Second event' });
batch.tryAdd({ body: 'Third event' });
await producer.sendBatch(batch);
await producer.close();
console.log('A batch of three events have been sent to the event hub');
} catch (error) {
throw e;
}
};
module.exports = { produce };

Controller.test.js:

const sinon = require('sinon');
const axios = require('axios');
const controller = require('./controller');
const producer = require('./Producer');
describe('execute', () => {
afterEach(() => {
sinon.restore();
});
it('call method to post', async () => {
sinon.stub(axios, 'post');
sinon.stub(producer, 'produce');
const req = { name: 'tina', dob: '2-12-2000', query: { param: 'thunder' } };
await controller.result(req, {});
sinon.assert.calledWithExactly(axios.post, '/login', 'tina', '2-12-2000');
sinon.assert.calledTwice(producer.produce);
});
});

测试结果：

execute
✓ call method to post

1 passing (5ms)
---------------|---------|----------|---------|---------|-------------------
File           | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
---------------|---------|----------|---------|---------|-------------------
All files      |   58.33 |       50 |      50 |   58.33 |                   
Producer.js   |   33.33 |      100 |       0 |   33.33 | 7-17              
controller.js |     100 |       50 |     100 |     100 | 6                 
---------------|---------|----------|---------|---------|-------------------