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How to stub a dependency in express middleware (express-validator/mocha/chai/sinon/proxyquire)

**Edit: Re-written with a simple example that works first:
So I've got a test file and 2 modules.
moduleA has a dependency, moduleB
// moduleA.js
const ModuleB = require('./moduleB');
function functionA() {
return 20 + ModuleB.functionB();
};
module.exports = { functionA };
// moduleB.js
const functionB = () => {
return 10;
}
module.exports = { functionB }
My test file stubs out functionB (returned from moduleB) using proxyquire:
const sinon = require('sinon');
const proxyquire = require('proxyquire');
describe('Unit Tests', function() {
it('should work', () => {
const mockedFn = sinon.stub();
mockedFn.returns(30);
const copyModuleA = proxyquire('./moduleA', {
'./moduleB': {
functionB: mockedFn
}
});
console.log(copyModuleA.functionA());
})
});
So it outputs 50 (stubbed functionB 30 + functionA 20)
Now I'm trying to take this example into my code:
moduleA in this case is a file called validation.js. It is dependent on moduleB, in this case a sequelize model, Person, with the function I want to mock: findOne
validation.js exports module.exports = { validateLogin };, a function that calls validate, which returns a function that uses Person.findOne()
So in my mind, as with the simple example, I need to create a stub, point to the validation module in proxyquire, and reference the dependency and its findOne function. Like this:
const stubbedFindOne = sinon.stub();
stubbedFindOne.resolves();
validationModule = proxyquire('../../utils/validation', {
'../models/Person': {
findOne: stubbedFindOne
}
});
This should stub Person.findOne in validation.js. But it doesn't seem to. And I have no idea why.
let validationModule;
describe('Unit Tests', () => {
before(() => {
const stubbedFindOne = sinon.stub();
stubbedFindOne.resolves();
validationModule = proxyquire('../../utils/validation', {
'../models/Person': {
findOne: stubbedFindOne
}
});
})
it.only('should return 422 if custom email validation fails', async() => {
const wrongEmailReq = { body: {email: 'nik#hotmail.com'} };
const res = {
statusCode: 500,
status: (code) => {this.statusCode = code; return this},
};
const validationFn = validationModule.validateLogin();
const wrongEmail = await validationFn(wrongEmailReq, res, ()=>{});
expect(wrongEmail.errors[0].msg).to.be.equal('Custom Authorisation Error');
return;
})
And this is my validation.js file:
const Person = require('../models/Person');
// parallel processing
const validate = validations => {
return async (req, res, next) => {
await Promise.all(validations.map(validation => validation.run(req)));
const errors = validationResult(req);
if (errors.isEmpty()) {
return next();
}
const error = new Error();
error.message = process.env.NODE_ENV === 'development'? 'Validation Failed':'Error';
error.statusCode = !errors.isEmpty()? 422:500;
error.errors = errors.array({onlyFirstError: true});
next(error);
return error;
};
};
const validateLogin = () => {
const validations = [
body('email')
.isString()
// snip
.custom(async (value, {req}) => {
try{
const person = await Person.findOne({ where: { email: value } });
if(!person) return Promise.reject('Custom Authorisation Error');
} catch(err) {
throw err;
}
})
.trim(),
];
return validate(validations);
}
module.exports = {
validateLogin
};

So the code in both the small sample and my app is correct, apart from how I stub the function. It shouldn't resolve or reject anything (I tried both out of desperation). It should return null in order to satisfy the conditional rather than jump to the catch block:
try{
const person = await Person.findOne({ where: { email: value } });
if(!person) return Promise.reject('Custom Authorisation Error');
} catch(err) {
throw err;
}
Hope the simple example helps someone else with proxyquire though

Testing controller with Jest - trying to inject a service to it with no luck

I'm new to testing in nodejs, I have an express backend split into microservices, and I'm currently trying to test the controller in the User directory.
The controller has a constructor which gets the user service - which is in charge of making DB operations. It's injected usually with awilix. I've been trying to inject my own mock object, but with no luck.
Here's what my userController.test.js looks like:
const request = require('supertest')
const UserController = require('../controllers/userController.js');
const { mockRequest, mockResponse } = require('../utils/interceptor')
const getAllUsers = jest.fn();
const userLogIn = jest.fn();
const getUserById = jest.fn();
const getUserByEmail = jest.fn();
const SearchUsers = jest.fn();
const changePassword = jest.fn();
const ChangeUserPicture = jest.fn();
const addUser = jest.fn();
getUserById.mockReturnValue({
id: 1,
name: 'user',
email: 'user#example.com'
})
userController = new UserController({
getAllUsers,
userLogIn,
getUserById,
getUserByEmail,
SearchUsers,
changePassword,
ChangeUserPicture,
addUser
});
describe('getuserbyid', () => {
test('should fetch a user by id', async () => {
let req = mockRequest();
req.params.id = 1;
const res = mockResponse();
await userController.getUserById(req, res)
.then((res) => console.log(res))
expect(res.mock).toBe({
name: 'user',
email: 'user#example.com'
});
expect(res.mock.calls.length).toBe(1);
})
})
As you can see, I'm passing in my own new object to the UserController constructor, yet when running the tests, I get that it's undefined.
Here's how it looks like in the controller:
async getUserById(req, res) {
try {
return JSON.stringify(await this.userService.getUserById(req));
}
catch (error) {
console.log(`There Was a Problem Getting User. error: ${error.message}`);
return (`Failed to get user, error: ${error.message}`);
}
}
I just get
Failed to get user, error: Cannot read property 'getUserById' of undefined

Sinon stub out module's function from a middleware

Based on this question, I need to also make a test for a middleware which also uses the db-connection.js file. The middleware file will look like this:
const dbConnection = require('./db-connection.js')
module.exports = function (...args) {
return async function (req, res, next) {
// somethin' somethin' ...
const dbClient = dbConnection.db
const docs = await dbClient.collection('test').find()
if (!docs) {
return next(Boom.forbidden())
}
}
}
, the database connection file do not change, which is:
const MongoClient = require('mongodb').MongoClient
const dbName = 'test'
const url = process.env.MONGO_URL
const client = new MongoClient(url, { useNewUrlParser: true,
useUnifiedTopology: true,
bufferMaxEntries: 0 // dont buffer querys when not connected
})
const init = () => {
return client.connect().then(() => {
logger.info(`mongdb db:${dbName} connected`)
const db = client.db(dbName)
})
}
/**
* #type {Connection}
*/
module.exports = {
init,
client,
get db () {
return client.db(dbName)
}
}
How the middleware works is by passing list of strings (that strings is roles), I have to query to the database and check whether there is a record of each roles. If the record exists, I will return next(), while if the record does not exist, I will return next(Boom.forbidden()) (next function with a 403 status code from Boom module).
Given the details above, how does one make a test to test out the return value of the middleware if the record exists or not? This means I have to assert the next() and next(Boom.forbidden) to be exact.

Based on the answer. You can create stubs for the req, res objects, and next function.
E.g.(Doesn't run, but it should work.)
const sinon = require('sinon');
describe('a', () => {
afterEach(() => {
sinon.restore();
});
it('should find some docs', async () => {
process.env.MONGO_URL = 'mongodb://localhost:27017';
const a = require('./a');
const dbConnection = require('./db-connection.js');
const dbStub = {
collection: sinon.stub().returnsThis(),
find: sinon.stub(),
};
sinon.stub(dbConnection, 'db').get(() => dbStub);
const req = {};
const res = {};
const next = sinon.stub();
const actual = await a()(req, res, next);
sinon.assert.match(actual, true);
sinon.assert.calledWithExactly(dbStub.collection, 'test');
sinon.assert.calledOnce(dbStub.find);
sinon.assert.calledOnce(next);
});
});

How to mock a function in another function nodejs

Trying to write a unittest for the below module in /utility/sqsThing.js. However I'm having diffuculty mocking the sqs.sendMessage method. Anyone know how I should go about this. I'm using the sinon library, and mocha for running the tests.
The function that I'm trying to unittest utility/sqsThing.js:
const AWS = require('aws-sdk');
AWS.config.update({ region: 'us-east-1' });
const sqs = new AWS.SQS({ apiVersion: '2012-11-05' });
const outputQueURL = 'https:awsUrl';
const SQSOutputSender = (results) => {
const params = {
MessageBody: JSON.stringify(results),
QueueUrl: outputQueURL,
};
// Method that I want to mock
sqs.sendMessage(params, function (err, data) {
if (err) {
console.log('Error');
} else {
console.log('Success', data.MessageId);
}
});
};
My attempt at mocking the sqs.sendMessage method in a unittest sqsThingTest.js:
const sqsOutputResultSender = require('../utility/sqsThing');
const AWS = require('aws-sdk');
const sqs = new AWS.SQS({ apiVersion: '2012-11-05' });
const mochaccino = require('mochaccino');
const { expect } = mochaccino;
const sinon = require('sinon');
describe('SQS thing test', function() {
beforeEach(function () {
sinon.stub(sqs, 'sendMessage').callsFake( function() { return 'test' });
});
afterEach(function () {
sqs.sendMessage.restore();
});
it('sqsOutputResultSender.SQSOutputSender', function() {
// Where the mock substitution should occur
const a = sqsOutputResultSender.SQSOutputSender('a');
expect(a).toEqual('test');
})
});
Running this unittest with mocha tests/unit/sqsThingTest.js however I get:
AssertionError: expected undefined to deeply equal 'test'.
info: Error AccessDenied: Access to the resource https://sqs.us-east-1.amazonaws.com/ is denied..
It looks like the mock did not replace the aws api call. Anyone know how I can mock sqs.SendMessage in my test?

You could use rewire js it is a library that lets you inject mocked properties into your module you want to test.
Your require statement would look something like this:
var rewire = require("rewire");
var sqsOutputResultSender = rewire('../utility/sqsThing');
Rewire will allow you to mock everything in the top-level scope of you sqsThing.js file.
Also you need to return the value of sqs.sendMessage this will remove the issue expected undefined to deeply equal 'test'
Your original file would look the same just with a return statement.
//utility/sqsThing.js
const AWS = require('aws-sdk');
AWS.config.update({ region: 'us-east-1' });
const sqs = new AWS.SQS({ apiVersion: '2012-11-05' });
const outputQueURL = 'https:awsUrl';
const SQSOutputSender = (results) => {
const params = {
MessageBody: JSON.stringify(results),
QueueUrl: outputQueURL,
};
// Method that I want to mock
return sqs.sendMessage(params, function (err, data) {
if (err) {
console.log('Error');
} else {
console.log('Success', data.MessageId);
}
});
};
You would then write your unit test as follows:
//sqsThingTest.js
var rewire = require("rewire");
var sqsOutputResultSender = rewire('../utility/sqsThing');
const mochaccino = require('mochaccino');
const { expect } = mochaccino;
const sinon = require('sinon');
describe('SQS thing test', function() {
beforeEach(function () {
sqsOutputResultSender.__set__("sqs", {
sendMessage: function() { return 'test' }
});
});
it('sqsOutputResultSender.SQSOutputSender', function() {
// Where the mock substitution should occur
const a = sqsOutputResultSender.SQSOutputSender('a');
expect(a).toEqual('test');
})
});
This example returns an object with a property of sendMessage but this could be replaces with a spy.
Rewire Docs

Try moving the declaration of sqsOutputResultSender after you have stubbed the sendmessage function
var sqsOutputResultSender;
const AWS = require('aws-sdk');
const sqs = new AWS.SQS({ apiVersion: '2012-11-05' });
const mochaccino = require('mochaccino');
const { expect } = mochaccino;
const sinon = require('sinon');
describe('SQS thing test', function() {
beforeEach(function () {
sinon.stub(sqs, 'sendMessage').callsFake( function() { return 'test' });
sqsOutputResultSender = require('../utility/sqsThing');
});
afterEach(function () {
sqs.sendMessage.restore();
});
it('sqsOutputResultSender.SQSOutputSender', function() {
// Where the mock substitution should occur
const a = sqsOutputResultSender.SQSOutputSender('a');
expect(a).toEqual('test');
})
});

Firebase Cloud Messaging for sending notification to all the registered devices not working

For my magazine app,I am using Firebase service.One function of this android app is whenever new article is published;notification of new article is sent to all the devices.
I am saving all the device tokens in db like this:
FCMToken
{
userid:deviceToken
}
So whenever new node is added in "published" key in firebase db,FCM function is triggered and messages is sent to all the devices:
Below is my code in javascript for FCM function:
'use strict'
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);
exports.sendNotification = functions.database.ref('/published/{msg_id}').onWrite(event => {
const snapshot = event.data;
// Only send a notification when a new message has been created.
if (snapshot.previous.val()) {
return;
}
const msg_id = event.params.msg_id;
const msg_val=admin.database().ref(`messages/${msg_id}`).once('value');
return msg_val.then(msgResult =>{
const msg_title=msgResult.val().title;
const user_id=msgResult.val().userId;
console.log('msg title is',msg_title);
console.log('We have a new article : ', msg_id);
const payload={
data : {
title:"New Article",
body: msg_title,
msgid : msg_id,
userid : user_id
}
};
// const deviceToken = admin.database().ref('/FCMToken/{user_id}').once('value');
admin.database().ref('/FCMToken').on("value", function(dbsnapshot)
{
dbsnapshot.forEach(function(childSnapshot) {
//var childKey = childSnapshot.key;
const childData = childSnapshot.val();
const deviceToken=console.log("device token" + childSnapshot.val());
return admin.messaging().sendToDevice(childData,payload).then(response=>{
console.log("This was notification feature")
console.log("response: ", response);
})
.catch(function(error)
{
console.log("error sending message",error)
});
});
});
});
});
For some reason,notification is only sent to only 1 device(the first token in FCM node).
Update:
I have updated my code and using promise,but for some reason it is still not working,just sending notification to first device token.
'use strict'
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);
exports.sendNotification = functions.database.ref('/published/{msg_id}').onWrite(event => {
const snapshot = event.data;
// Only send a notification when a new message has been created.
if (snapshot.previous.val()) {
return;
}
const msg_id = event.params.msg_id;
const msg_val=admin.database().ref(`messages/${msg_id}`).once('value');
return msg_val.then(msgResult =>{
const msg_title=msgResult.val().title;
const user_id=msgResult.val().userId;
console.log('msg title is',msg_title);
console.log('We have a new article : ', msg_id);
const payload={
data : {
title:"New Article",
body: msg_title,
msgid : msg_id,
userid : user_id
}
};
const promises=[];
// const deviceToken = admin.database().ref('/FCMToken/{user_id}').once('value');
admin.database().ref('/FCMToken').once('value').then(function(dbsnapshot)
{
dbsnapshot.forEach(function(childSnapshot) {
//var childKey = childSnapshot.key;
const childData = childSnapshot.val();
const deviceToken=console.log("device token" + childSnapshot.val());
const promise = admin.messaging().sendToDevice(childData,payload).then(response=>{
promises.push(promise)
console.log("This was notification feature")
console.log("response: ", response);
})
return Promise.all(promises)
.catch(function(error)
{
console.log("error sending message",error)
});
});
});
});
});
Response object is giving this output: response: { results: [ { error: [Object] } ],
canonicalRegistrationTokenCount: 0,
failureCount: 1,
successCount: 0,
multicastId: 6411440389982586000 }

You're not using promises correctly throughout your function. There are two things wrong.
First, you should be querying the database using once() instead of on(), and using the promise returned from it in order to proceed to the next item of work:
admin.database().ref('/FCMToken').on("value")
.then(result => /* continue your work here */)
Also, you can't return a promise out of the forEach loop. Instead, you need to return a promise at the top level of the function, as the very last step in the function. This promise needs to resolve when all of the work is done in this function. For your function, this means when all of the messages are sent. You'll have to collect all the promises for all of the messages in an array, then return a single promise that resolves when they all resolve. The general form of that looks like this:
const promises = []
dbsnapshot.forEach(function(childSnapshot) {
// remember each promise for each message sent
const promise = return admin.messaging().sendToDevice(...)
promises.push(promise)
})
// return a single promise that resolves when everything is done
return Promise.all(promises)
Please take care to learn how promises work in JavaScript. You won't be able to write effective functions without dealing with promises correctly.

So I figured out another method to get values.
const tokens= Object.keys(tokensSnapshot.val()).map(e => tokensSnapshot.val()[e]);
Below is my complete method:
'use strict'
const functions = require('firebase-functions');
const admin = require('firebase-admin');
//Object.values = require('object.values');
admin.initializeApp(functions.config().firebase);
exports.sendNotification = functions.database.ref('/published/{msg_id}').onWrite(event => {
const snapshot = event.data;
// Only send a notification when a new message has been created.
if (snapshot.previous.val()) {
return;
}
const msg_id = event.params.msg_id;
const msg_val=admin.database().ref(`messages/${msg_id}`).once('value');
return msg_val.then(msgResult =>{
const msg_title=msgResult.val().title;
const user_id=msgResult.val().userId;
console.log('msg title is',msg_title);
console.log('We have a new article : ', msg_id);
const payload={
data : {
title:"New Article",
body: msg_title,
msgid : msg_id,
userid : user_id
}
};
const getDeviceTokensPromise = admin.database().ref('/FCMToken').once('value');
return Promise.all([getDeviceTokensPromise, msg_title]).then(results => {
const tokensSnapshot = results[0];
const msgi = results[1];
if (!tokensSnapshot.hasChildren()) {
return console.log('There are no notification tokens to send to.');
}
console.log('There are', tokensSnapshot.numChildren(), 'tokens to send notifications to.');
console.log("tokenslist",tokensSnapshot.val());
const tokens= Object.keys(tokensSnapshot.val()).map(e => tokensSnapshot.val()[e]);
//var values = Object.keys(o).map(e => obj[e])
return admin.messaging().sendToDevice(tokens, payload).then(response => {
// For each message check if there was an error.
const tokensToRemove = [];
response.results.forEach((result, index) => {
const error = result.error;
if (error) {
console.error('Failure sending notification to', tokens[index], error);
// Cleanup the tokens who are not registered anymore.
}
});
return Promise.all(tokensToRemove);
});
});
});
});