nodejs - test failing but callback being called - node.js

Question

I have a module which I export and which has a method editHeroImage which I am trying to test using mocha, chai and sinon. The modules has two objects that are passed as arguments, connection and queries. These are mySql objects, one containing the connection to the database and the other the query strings which are defined in their separate modules. The expObj which I am exporting and trying to test is a "helper" module.
I have successfully tested other methods of this module in the same way I am trying to test this method, but, however when I run into methods which use the async module for some reason, my tests no longer behave as expected. I wonder if I am missing something in this particular case, because I have tested other modules and methods which also use async and have not come across this behaviour.
When I run the tests, it logs "HELLO!" as expected but the assertion that the callbackSpy has been called, fails.
I am losing my mind here! Please help! What is going on? Could there be contamination between test suits?
Method under test:
expObj.editHeroImage = function(connection, queries, postId, postData, callback) {
async.waterfall([
function(next) {
var qString = queries.getSinglePostById();
connection.query(qString, [postId], function(err, results) {
if (err) {
return next(err);
}
if (!results.length) {
console.log('NO POST FOUND WITH ID ' + postId);
return callback();
}
next(null, results[0].hero_image);
});
},
function(heroImageId, next) {
if (!heroImageId) {
console.log('HERO IMAGE IS NEW - NEXT TICK!');
return next();
}
// Delete resized images of hero image
var queryStr = queries.deleteResizedImages();
var resizedVals = [heroImageId];
connection.query(queryStr, resizedVals, function(err) {
if (err) {
return callback(err);
}
console.log('DELETED RESIZED IMAGES OF HERO IMAGE ' + heroImageId);
var qString = queries.updateHeroImagePath();
var values = [postData.hero_image, heroImageId];
return connection.query(qString, values, function(err, results) {
if (err) {
return next(err);
}
console.log('UPDATED HERO IMAGE ' + heroImageId + ' WITH PATH ' + postData.hero_image);
next('break');
});
});
},
function addHeroImage(next) {
var qString = queries.insertImage();
var values = [postData.hero_image, postId];
connection.query(qString, values, function(err, results) {
if (err) {
return next(err);
}
next(null, results.insertId);
});
},
function addHeroImagePathToPost(heroImageId, next) {
var qString = queries.saveHeroImageId();
var values = [heroImageId, postId];
connection.query(qString, values, function(err) {
if (err) {
return next(err);
}
next();
});
}
], function(err) {
if (err && err !== 'break') {
return callback(err);
}
console.log('HELLO!');
callback(null);
});
};
Test, with set-up:
'use strict';
var chai = require('chai');
var sinonChai = require("sinon-chai");
var proxyquire = require('proxyquire');
var sinon = require('sinon');
chai.use(sinonChai);
var expect = chai.expect;
describe('HELPERS', function() {
var testedModule,
callbackSpy,
fakeConnectionObj,
fakeQueriesObj,
fakePost,
fakeSnakeCaseObj,
queryStub,
connectionStub,
manageStub,
fakeCamelCaseObj;
beforeEach(function() {
fakePost = {};
fakeConnectionObj = {};
fakeQueriesObj = {
getPostIdFromImage: function() {},
insertResizedImages: function() {},
createPost: function() {},
getPostImages: function() {},
getPostsAlternativesImages: function() {},
getSinglePostById: function() {},
getAllImages: function() {},
insertImage: function() {},
deleteMainImage: function() {},
deleteResizedImages: function() {},
updateHeroImagePath: function() {},
saveHeroImageId: function() {}
};
afterEach(function() {
queryStub.resetBehavior();
});
fakeSnakeCaseObj = {
sub_title: '123',
hero_image: '456'
};
fakeCamelCaseObj = {
subTitle: '123',
heroImage: '456'
};
callbackSpy = sinon.spy();
queryStub = sinon.stub();
manageStub = sinon.stub();
connectionStub = {query: queryStub};
testedModule = proxyquire('./../../../../lib/modules/mySql/workers/helpers', {
'./../../../factories/notification-service': {
select: function() {
return {manageSns: manageStub};
}
}
});
});
it('edits hero image', function() {
var _post = {
id: '123',
title: 'vf',
sub_title: 'vf',
slug: 'vf',
reading_time: 4,
created_at: '123',
published_at: '123',
deleted_on: false,
hero_image: 'hero_image_path'
};
var _postId = '123';
queryStub.onCall(0).callsArgWith(2, null, [{hero_image: '55'}]);
queryStub.onCall(1).callsArgWith(2, null);
queryStub.onCall(2).callsArgWith(2, null);
testedModule.editHeroImage(connectionStub, fakeQueriesObj, _postId, _post, function() {
console.log(arguments); // --> {'0': null} as expected
callbackSpy.apply(null, arguments);
});
expect(callbackSpy).has.been.calledWith(null);
});
});

Answer 1

Your assertion is probably executing before your async function has returned.
There are a number of ways to ensure your async functions have finished executing. The cleanest is to format your mocha test differently.
describe('...', function () {
var callbackSpy;
before(function () {
var _post = {
id: '123',
title: 'vf',
sub_title: 'vf',
slug: 'vf',
reading_time: 4,
created_at: '123',
published_at: '123',
deleted_on: false,
hero_image: 'hero_image_path'
};
var _postId = '123';
queryStub.onCall(0).callsArgWith(2, null, [{
hero_image: '55'
}]);
queryStub.onCall(1).callsArgWith(2, null);
queryStub.onCall(2).callsArgWith(2, null);
return testedModule.editHeroImage(connectionStub, fakeQueriesObj, _postId, _post, function () {
console.log(arguments); // --> {'0': null} as expected
callbackSpy.apply(null, arguments);
});
});
it('edits hero image', function () {
expect(callbackSpy).has.been.calledWith(null);
});
});
Notice that I have wrapped your assertion in a describe block so we can use before. Your actual logic for setting up stubs and executing the class has been moved to the before block and a return added, this ensures the async function is complete before moving on to your assertions.
Your other tests may have passed, but they will also be susceptible to this and it is purely a timing issue.

Answer 2

Indeed #Varedis was right about it being a timing issue. However using your suggestion of wrapping the assertion in a describe bloack and using the before function to set-up the test resulted in my stubs no longer working correctly. However taking your suggestion about timing into account I managed to solve the issue by using the done callback within my test suit. By keeping the set-up I made a slight change and my tests suddenly passed:
it('edits hero image', function(done) {
var _post = {
id: '123',
title: 'vf',
sub_title: 'vf',
slug: 'vf',
reading_time: 4,
created_at: '123',
published_at: '123',
deleted_on: false,
hero_image: 'hero_image_path'
};
var _postId = '123';
queryStub.onCall(0).callsArgWith(2, null, [{hero_image: '55'}]);
queryStub.onCall(1).callsArgWith(2, null);
queryStub.onCall(2).callsArgWith(2, null);
testedModule.editHeroImage(connectionStub, fakeQueriesObj, _postId, _post, function() {
callbackSpy.apply(null, arguments);
expect(callbackSpy).has.been.calledWith(null);
expect(callbackSpy).has.not.been.calledWith('FDgdjghg');
done();
});
});