Develop Reference

Why does injecting 'ng' in unit tests change promise handling behaviour?

The following service uses $q.when to wrap a third-party promise:
// service.js
angular.module('test', [])
.service('pouchdb', function($q, $window) {
var db = new $window.PouchDB('test');
this.info = function() {
return $q.when(db.info.apply(db, arguments));
};
});
Corresponding unit test:
describe('Failing Q when tests', function() {
beforeEach(module('test'));
var $rootScope, pouchdb;
beforeEach(inject(function(_$rootScope_, pouchdb) {
$rootScope = _$rootScope_;
pouchdb = pouchdb;
}));
it('should resolve a promise', function(done) {
// FIXME: never resolves
pouchdb.info()
.then(function(info) {
expect(info).toBeDefined();
})
.finally(done);
$rootScope.$apply();
});
});
pouchdb.info never resolves and Jasmine times out. However, if I manually inject ng, the spec works as expected:
describe('Working Q when tests', function() {
var pouchdb;
beforeEach(function() {
var $injector = angular.injector(['ng', 'test']);
var pouchDB = $injector.get('pouchdb');
pouchdb = pouchDB('db');
});
it('should resolve a promise', function(done) {
pouchdb.info()
.then(function(info) {
expect(info).toBeDefined();
})
.finally(done);
});
});
Could anyone explain why;
The first spec doesn't resolve
The second spec does (injecting ng)
It doesn't need $rootScope.$apply
Whether it's a good pattern to use

Are you using angular-mocks? https://docs.angularjs.org/api/ngMock
The only reason why I think that you'd need to inject 'ng' manually is if there is no ng-app initializing your app, at least according to https://docs.angularjs.org/api/ng/function/angular.module
If you use angular-mocks it takes care of that for you https://github.com/angular/angular.js/blob/master/src/ngMock/angular-mocks.js#L1785
Can't think of any other reason as to why this problem would occur.

Mocking asynchronous service function using angular/karma/jasmine

The test in this code does not succeed. I can't seem to successfully test the return of an asynchronous function.
describe('mocking services', function () {
var someService, deferred;
beforeEach(function () {
module(function($provide){
$provide.factory('someService', function($q){
return{
trySynch: function(){
return 33;
},
tryAsynch: function(){
deferred = $q.defer();
return deferred.promise;
}
};
});
});
inject(function (_someService_) {
someService = _someService_;
});
});
it('should be able to test values from both functions', function () {
expect(someService.trySynch()).toEqual(33);
var retVal;
someService.tryAsynch().then(function(r){
retVal = r;
});
deferred.resolve(44);
expect(retVal).toEqual(44);
});
});
When I run it I get the following error:
Chrome 36.0.1985 (Mac OS X 10.9.4) mocking services should be able to test values from both functions FAILED
Expected undefined to equal 44.
Error: Expected undefined to equal 44.
at null.<anonymous> (/Users/selah/WebstormProjects/macrosim-angular/test/spec/services/usersAndRoles-service-test.js:34:24)
How can I make this test pass?

When mocking async calls with $q, you need to use $rootScope.$apply() because of how $q is implemented.
Specifically, the .then method does not get called synchronously, it is designed to always be async, regardless of how it was called - sync or async.
To achieve that, $q is integrated with $rootScope. Therefore, in your unit tests, you need to notify the $rootScope that something was changed (ie - trigger a digest cycle). To do that, you call $rootScope.$apply()
See here (specifically the "Differences between Kris Kowal's Q and $q section")
Working code looks like this:
describe('mocking services', function () {
var someService, deferred, rootScope;
beforeEach(function () {
module(function($provide){
$provide.factory('someService', function($q){
return{
trySynch: function(){
return 33;
},
tryAsynch: function(){
deferred = $q.defer();
return deferred.promise;
}
};
});
});
inject(function ($injector) {
someService = $injector.get('someService');
rootScope = $injector.get('$rootScope');
});
});
it('should be able to test values from both functions', function () {
expect(someService.trySynch()).toEqual(33);
var retVal;
someService.tryAsynch().then(function(r){
retVal = r;
});
deferred.resolve(44);
rootScope.$apply();
expect(retVal).toEqual(44);
});
});

$q's deferred is still resolving asynchronously.
Quick test, albeit in an older version of Angular: http://plnkr.co/edit/yg2COXG0TWBYniXOwJYb
This test should work:
it('should be able to test values from both functions', function (done) {
expect(someService.trySynch()).toEqual(33);
someService.tryAsynch().then(function(r){
expect(r).toEqual(44);
done();
});
deferred.resolve(44);
});

If I run rootScope.$apply() before my expect clause that tests my asynchronous function then the test succeeds. Also, it fails if I supply an incorrect value, as I would expect it to.
So my test is functional, but I don't however understand why rootScope.$apply() is important here, so if anyone wants to copy my code and provide an explanation I will gladly mark your answer as the correct answer!
My working test code looks like this:
describe('mocking services', function () {
var someService, deferred, rootScope;
beforeEach(function () {
module(function($provide){
$provide.factory('someService', function($q){
return{
trySynch: function(){
return 33;
},
tryAsynch: function(){
deferred = $q.defer();
return deferred.promise;
}
};
});
});
inject(function ($injector) {
someService = $injector.get('someService');
rootScope = $injector.get('$rootScope');
});
});
it('should be able to test values from both functions', function () {
expect(someService.trySynch()).toEqual(33);
var retVal;
someService.tryAsynch().then(function(r){
retVal = r;
});
deferred.resolve(44);
rootScope.$apply();
expect(retVal).toEqual(44);
});
});

Test a controller with success() and error ()

I'm trying to work out the best way to unit test success and error callbacks in controllers. I am able to mock out service methods, as long as the controller only uses the default $q functions such as 'then' (see the example below). I'm having an issue when the controller responds to a 'success' or 'error' promise. (Sorry if my terminology is not correct).
Here is an example controller \ service
var myControllers = angular.module('myControllers');
myControllers.controller('SimpleController', ['$scope', 'myService',
function ($scope, myService) {
var id = 1;
$scope.loadData = function () {
myService.get(id).then(function (response) {
$scope.data = response.data;
});
};
$scope.loadData2 = function () {
myService.get(id).success(function (response) {
$scope.data = response.data;
}).error(function(response) {
$scope.error = 'ERROR';
});
};
}]);
cocoApp.service('myService', [
'$http', function($http) {
function get(id) {
return $http.get('/api/' + id);
}
}
]);
I have the following test
'use strict';
describe('SimpleControllerTests', function () {
var scope;
var controller;
var getResponse = { data: 'this is a mocked response' };
beforeEach(angular.mock.module('myApp'));
beforeEach(angular.mock.inject(function($q, $controller, $rootScope, $routeParams){
scope = $rootScope;
var myServiceMock = {
get: function() {}
};
// setup a promise for the get
var getDeferred = $q.defer();
getDeferred.resolve(getResponse);
spyOn(myServiceMock, 'get').andReturn(getDeferred.promise);
controller = $controller('SimpleController', { $scope: scope, myService: myServiceMock });
}));
it('this tests works', function() {
scope.loadData();
expect(scope.data).toEqual(getResponse.data);
});
it('this doesnt work', function () {
scope.loadData2();
expect(scope.data).toEqual(getResponse.data);
});
});
The first test passes and the second fails with the error "TypeError: Object doesn't support property or method 'success'". I get that in this instance that getDeferred.promise
does not have a success function. Okay here is the question, what is a nice way to write this test so that I can test the 'success', 'error' & 'then' conditions of a mocked service ?
I'm starting to think that I should avoid the use of success() and error() in my controllers...
EDIT
So after thinking about this some more, and thanks to the detailed answer below, I've come to the conclusion that the handling the success and error callbacks in the controller is bad. As HackedByChinese mentions below success\error is syntactic sugar that is added by $http. So, in actual fact, by trying to handle success \ error I am letting $http concerns leak into my controller, which is exactly what I was trying to avoid by wrapping the $http calls in a service. The approach I'm going to take is to change the controller not to use success \ error:
myControllers.controller('SimpleController', ['$scope', 'myService',
function ($scope, myService) {
var id = 1;
$scope.loadData = function () {
myService.get(id).then(function (response) {
$scope.data = response.data;
}, function (response) {
$scope.error = 'ERROR';
});
};
}]);
This way I can test the error \ success conditions by calling resolve() and reject() on the deferred object:
'use strict';
describe('SimpleControllerTests', function () {
var scope;
var controller;
var getResponse = { data: 'this is a mocked response' };
var getDeferred;
var myServiceMock;
//mock Application to allow us to inject our own dependencies
beforeEach(angular.mock.module('myApp'));
//mock the controller for the same reason and include $rootScope and $controller
beforeEach(angular.mock.inject(function($q, $controller, $rootScope, $routeParams) {
scope = $rootScope;
myServiceMock = {
get: function() {}
};
// setup a promise for the get
getDeferred = $q.defer();
spyOn(myServiceMock, 'get').andReturn(getDeferred.promise);
controller = $controller('SimpleController', { $scope: scope, myService: myServiceMock });
}));
it('should set some data on the scope when successful', function () {
getDeferred.resolve(getResponse);
scope.loadData();
scope.$apply();
expect(myServiceMock.get).toHaveBeenCalled();
expect(scope.data).toEqual(getResponse.data);
});
it('should do something else when unsuccessful', function () {
getDeferred.reject(getResponse);
scope.loadData();
scope.$apply();
expect(myServiceMock.get).toHaveBeenCalled();
expect(scope.error).toEqual('ERROR');
});
});

As someone had mentioned in a deleted answer, success and error are syntactic sugar added by $http so they aren't there when you create your own promise. You have two options:
1 - Don't mock the service and use $httpBackend to setup expectations and flush
The idea is to let your myService act like it normally would without knowing it's being tested. $httpBackend will let you set up expectations and responses, and flush them so you can complete your tests synchronously. $http won't be any wiser and the promise it returns will look and function like a real one. This option is good if you have simple tests with few HTTP expectations.
'use strict';
describe('SimpleControllerTests', function () {
var scope;
var expectedResponse = { name: 'this is a mocked response' };
var $httpBackend, $controller;
beforeEach(module('myApp'));
beforeEach(inject(function(_$rootScope_, _$controller_, _$httpBackend_){
// the underscores are a convention ng understands, just helps us differentiate parameters from variables
$controller = _$controller_;
$httpBackend = _$httpBackend_;
scope = _$rootScope_;
}));
// makes sure all expected requests are made by the time the test ends
afterEach(function() {
$httpBackend.verifyNoOutstandingExpectation();
$httpBackend.verifyNoOutstandingRequest();
});
describe('should load data successfully', function() {
beforeEach(function() {
$httpBackend.expectGET('/api/1').response(expectedResponse);
$controller('SimpleController', { $scope: scope });
// causes the http requests which will be issued by myService to be completed synchronously, and thus will process the fake response we defined above with the expectGET
$httpBackend.flush();
});
it('using loadData()', function() {
scope.loadData();
expect(scope.data).toEqual(expectedResponse);
});
it('using loadData2()', function () {
scope.loadData2();
expect(scope.data).toEqual(expectedResponse);
});
});
describe('should fail to load data', function() {
beforeEach(function() {
$httpBackend.expectGET('/api/1').response(500); // return 500 - Server Error
$controller('SimpleController', { $scope: scope });
$httpBackend.flush();
});
it('using loadData()', function() {
scope.loadData();
expect(scope.error).toEqual('ERROR');
});
it('using loadData2()', function () {
scope.loadData2();
expect(scope.error).toEqual('ERROR');
});
});
});
2 - Return a fully-mocked promise
If the thing you're testing has complicated dependencies and all the set-up is a headache, you may still want to mock the services and the calls themselves as you have attempted. The difference is that you'll want to fully mock promise. The downside of this can be creating all the possible mock promises, however you could make that easier by creating your own function for creating these objects.
The reason this works is because we pretend that it resolves by invoking the handlers provided by success, error, or then immediately, causing it to complete synchronously.
'use strict';
describe('SimpleControllerTests', function () {
var scope;
var expectedResponse = { name: 'this is a mocked response' };
var $controller, _mockMyService, _mockPromise = null;
beforeEach(module('myApp'));
beforeEach(inject(function(_$rootScope_, _$controller_){
$controller = _$controller_;
scope = _$rootScope_;
_mockMyService = {
get: function() {
return _mockPromise;
}
};
}));
describe('should load data successfully', function() {
beforeEach(function() {
_mockPromise = {
then: function(successFn) {
successFn(expectedResponse);
},
success: function(fn) {
fn(expectedResponse);
}
};
$controller('SimpleController', { $scope: scope, myService: _mockMyService });
});
it('using loadData()', function() {
scope.loadData();
expect(scope.data).toEqual(expectedResponse);
});
it('using loadData2()', function () {
scope.loadData2();
expect(scope.data).toEqual(expectedResponse);
});
});
describe('should fail to load data', function() {
beforeEach(function() {
_mockPromise = {
then: function(successFn, errorFn) {
errorFn();
},
error: function(fn) {
fn();
}
};
$controller('SimpleController', { $scope: scope, myService: _mockMyService });
});
it('using loadData()', function() {
scope.loadData();
expect(scope.error).toEqual("ERROR");
});
it('using loadData2()', function () {
scope.loadData2();
expect(scope.error).toEqual("ERROR");
});
});
});
I rarely go for option 2, even in big applications.
For what it's worth, your loadData and loadData2 http handlers have an error. They reference response.data but the handlers will be called with the parsed response data directly, not the response object (so it should be data instead of response.data).

Don't mix concerns!
Using $httpBackend inside a controller is a bad Idea since you are mixing concerns inside your Test. Whether you retrieve data from an Endpoint or not is not a concern of the Controller, is a concern of the DataService you are calling.
You can see this more clearly if you change the Endpoint Url inside the service you will then have to modify both tests: the service Test and the Controller Test.
Also as previously mentioned, the use of success and error are syntactic sugar and we should stick to the use of then and catch. But in reality you may find yourself in the need of testing "legacy" code. So for that I'm using this function:
function generatePromiseMock(resolve, reject) {
var promise;
if(resolve) {
promise = q.when({data: resolve});
} else if (reject){
promise = q.reject({data: reject});
} else {
throw new Error('You need to provide an argument');
}
promise.success = function(fn){
return q.when(fn(resolve));
};
promise.error = function(fn) {
return q.when(fn(reject));
};
return promise;
}
By calling this function you will get a true promise that respond to then and catch methods when you need to and will also work for the success or error callbacks. Note that the success and error returns a promise itself so it will work with chained then methods.
(NOTE: On the 4th and 6th line the function returns resolve and reject values inside the data property of an object. This is to mock the Behavior of $http since it returns the data, http Status etc.)

Yes, do not use $httpbackend in your controller, because we don't need to make real requests, you just need to make sure that one unit is doing it's job exactly as expected, have a look on this simple controller tests, it's easy to understand
/**
* #description Tests for adminEmployeeCtrl controller
*/
(function () {
"use strict";
describe('Controller: adminEmployeeCtrl ', function () {
/* jshint -W109 */
var $q, $scope, $controller;
var empService;
var errorResponse = 'Not found';
var employeesResponse = [
{id:1,name:'mohammed' },
{id:2,name:'ramadan' }
];
beforeEach(module(
'loadRequiredModules'
));
beforeEach(inject(function (_$q_,
_$controller_,
_$rootScope_,
_empService_) {
$q = _$q_;
$controller = _$controller_;
$scope = _$rootScope_.$new();
empService = _empService_;
}));
function successSpies(){
spyOn(empService, 'findEmployee').and.callFake(function () {
var deferred = $q.defer();
deferred.resolve(employeesResponse);
return deferred.promise;
// shortcut can be one line
// return $q.resolve(employeesResponse);
});
}
function rejectedSpies(){
spyOn(empService, 'findEmployee').and.callFake(function () {
var deferred = $q.defer();
deferred.reject(errorResponse);
return deferred.promise;
// shortcut can be one line
// return $q.reject(errorResponse);
});
}
function initController(){
$controller('adminEmployeeCtrl', {
$scope: $scope,
empService: empService
});
}
describe('Success controller initialization', function(){
beforeEach(function(){
successSpies();
initController();
});
it('should findData by calling findEmployee',function(){
$scope.findData();
// calling $apply to resolve deferred promises we made in the spies
$scope.$apply();
expect($scope.loadingEmployee).toEqual(false);
expect($scope.allEmployees).toEqual(employeesResponse);
});
});
describe('handle controller initialization errors', function(){
beforeEach(function(){
rejectedSpies();
initController();
});
it('should handle error when calling findEmployee', function(){
$scope.findData();
$scope.$apply();
// your error expectations
});
});
});
}());

AngularJs unit test - mocked promise not executing "then"

We're unit testing our controllers. We've successfully mocked the call to our REST service layer and verified that it is indeed being called with the given data. Now however we'd like to test that in our controller the execution of the then promise changes the location.path:
controller:
(function () {
app.controller('registerController', ['$scope', '$location', '$ourRestWrapper', function ($scope, $location, $ourRestWrapper) {
$scope.submitReg = function(){
// test will execute this
var promise = $ourRestWrapper.post('user/registration', $scope.register);
promise.then(function(response) {
console.log("success!"); // test never hits here
$location.path("/");
},
function(error) {
console.log("error!"); // test never hits here
$location.path("/error");
}
);
};
$ourRestWrapper.post(url,data) just wraps Restangular.all(url).post(data)..
Our Test:
(function () {
describe("controller: registerController", function() {
var scope, location, restMock, controller, q, deferred;
beforeEach(module("ourModule"));
beforeEach(function() {
restMock = {
post: function(url, model) {
console.log("deferring...");
deferred = q.defer();
return deferred.promise;
}
};
});
// init controller for test
beforeEach(inject(function($controller, $rootScope, $ourRestWrapper, $location, $q){
scope = $rootScope.$new();
location = $location;
q = $q;
controller = $controller('registerController', {
$scope: scope, $location: location, $ourRestWrapper: restMock});
}));
it('should call REST layer with registration request', function() {
scope.register = {data:'test'};
spyOn(restMock, 'post').andCallThrough();
scope.submitReg();
deferred.resolve();
// successfull
expect(restMock.post).toHaveBeenCalledWith('user/registration',scope.register);
expect(restMock.post.calls.length).toEqual(1);
// fail: Expected '' to be '/'.
expect(location.path()).toBe('/');
});
In our console we see "deferring..." and the first two expectations succeed. Why will it not call the then block (i.e. set the location)?

Cache the $rootscope object when you get it from the injector and call $rootScope.$apply() immediately after deferred.resolve().

How do I mock the result in a $http.get promise when testing my AngularJS controller?

After much reading, it seems that the recommended way to call a web service from an AngularJS controller is to use a factory and return a promise from that.
Here I have a simple factory which calls a sample API.
myApp.factory('MyFactory', ['$http',function($http) {
var people = {
requestPeople: function(x) {
var url = 'js/test.json';
return $http.get(url);
}
};
return people;
}]);
And this is how I call it in the controller
myApp.controller('MyCtrl1', ['$scope', 'MyFactory', function ($scope, MyFactory) {
MyFactory.requestPeople(22).then(function(result) {
$scope.peopleList = result;
});
}]);
While it works fine, I would like to be able to mock the result that is passed in when then is called. Is this possible?
My attempt so far has produced nothing. This is my attempt:
//Fake service
var mockService = {
requestPeople: function () {
return {
then: function () {
return {"one":"three"};
}
}
}
};
//Some setup
beforeEach(module('myApp.controllers'));
var ctrl, scope;
beforeEach(inject(function ($rootScope, $controller) {
scope = $rootScope.$new();
ctrl = $controller('MyCtrl1', { $scope: scope, MyFactory: mockService });
}));
//Test
it('Event Types Empty should default to false', inject(function () {
expect(scope.peopleList.one).toBe('three');
}));
The error that I get when running this in karma runner, is
TypeError: 'undefined' is not an object (evaluating 'scope.peopleList.one')
How can I get this test working with my mocked data?

I don't think $httpBackend is what you're after here, you want the whole factory to be mocked without it having a dependency on $http?
Take a look at $q, in particular the code sample under the Testing header. Your issue might be resolved with code that looks like this:
'use strict';
describe('mocking the factory response', function () {
beforeEach(module('myApp.controllers'));
var scope, fakeFactory, controller, q, deferred;
//Prepare the fake factory
beforeEach(function () {
fakeFactory = {
requestPeople: function () {
deferred = q.defer();
// Place the fake return object here
deferred.resolve({ "one": "three" });
return deferred.promise;
}
};
spyOn(fakeFactory, 'requestPeople').andCallThrough();
});
//Inject fake factory into controller
beforeEach(inject(function ($rootScope, $controller, $q) {
scope = $rootScope.$new();
q = $q;
controller = $controller('MyCtrl1', { $scope: scope, MyFactory: fakeFactory });
}));
it('The peopleList object is not defined yet', function () {
// Before $apply is called the promise hasn't resolved
expect(scope.peopleList).not.toBeDefined();
});
it('Applying the scope causes it to be defined', function () {
// This propagates the changes to the models
// This happens itself when you're on a web page, but not in a unit test framework
scope.$apply();
expect(scope.peopleList).toBeDefined();
});
it('Ensure that the method was invoked', function () {
scope.$apply();
expect(fakeFactory.requestPeople).toHaveBeenCalled();
});
it('Check the value returned', function () {
scope.$apply();
expect(scope.peopleList).toBe({ "one": "three" });
});
});
I've added some tests around what $apply does, I didn't know that until I started playing with this!
Gog