Where should $httpBackend.expect() go? - angularjs

The following test passes:
admin.controller.js
angular
.module('mean-starter')
.controller('AdminController', AdminController);
function AdminController(User, Auth, $state) {
var vm = this;
User
.list()
.success(function(data) {
vm.users = data;
})
.error(function() {
console.log('Problem getting users.');
});
vm.delete = function(id) {
User
.delete(id)
.success(function(data) {
if (Auth.getCurrentUser()._id === id) Auth.logout(); // deleting yourself
else $state.reload();
})
.error(function() {
console.log('Problem deleting user.');
});
};
}
admin.controller.spec.js
describe('AdminController', function() {
var AdminController, $httpBackend;
beforeEach(module('mean-starter'));
beforeEach(module('templates'));
beforeEach(inject(function($controller, $rootScope, _$httpBackend_) {
$httpBackend = _$httpBackend_;
AdminController = $controller('AdminController');
}));
afterEach(function() {
$httpBackend.verifyNoOutstandingExpectation();
$httpBackend.verifyNoOutstandingRequest();
});
it('gets users', function() {
$httpBackend
.expectGET('/users')
.respond('foo');
$httpBackend.flush();
});
});
I wouldn't expect it to. Here is what I expected to happen:
The controller is instantiated in the beforeEach.
User.list() gets run.
The $http isn't yet overridden by $httpBackend, so the request goes out normally.
$httpBackend.expectGET('/users').respond('foo') expects GET /users. And says, "I'll respond with 'foo' if I get that request".
$httpBackend.flush() says "Send out the defined responses for any of the requests that $httpBackend received."
.expectGET fails because it doesn't receive it's request (the request happened before the expectation).
.flush() throws an error because there's nothing to flush.
I'm not getting the outcomes I was expecting, so something about my logic above must be wrong - what is it?

The $http isn't yet overridden by $httpBackend, so the request goes out normally.
This is not a correct assumption. $httpBackend is used automatically in unit tests (it's part of the ng-mocks module that's used in unit tests). So whether you use $httpBackend or not in your unit test code, it's there and it's processing all the $http requests that your code makes.
Think about it, if it wasn't doing this, your unit tests could make real requests.
EDIT
For cases like this, where the controller is making an HTTP request as soon as it's instantiated, I like to put the $httpBackend.expectGET() call in the beforeEach block right before you instantiate the controller.
I would also flush() the backend in the beforeEach block as well. This, I think, makes it clear that these requests happen at controller startup. And it means I don't have to make this expectation in every unit test.

Related

Testing controller that depends on a service which is based on resource

I have a controller that calls a Service which is a wrapper for a Resource. Like this:
app.factory("Service", ["$resource", function ($resource) {
return $resource("/api/Service/get");
}]);
Return value of the service's method is assigned to a variable within the controller. Normally, the variable is of type Resource and it contains a promise. When the promise is resolved, the variable is populated with all values returned from the backend.
I track then on the promise in order to modify the model received from the backend. Like so:
this.model = Service.get();
this.model.$promise.then(function(data) {
// do something with data
});
I need to test the value of the resulting model variable in my controller.
The only way I found to do this, is to use $httpBackend with a real implementation of my Service. However, this is ugly because then, testing my controller, I have to pass request path "api/Service/get" to the httpBackend.when() in order for it to respond with some value.
An excerpt form my test:
// call Controller
$httpBackend.when('GET', '/api/Service/get').respond(someData);
$httpBackend.flush();
expect(scope.model.property).toBe(null);
This seems and feels utterly wrong. The whole point of using a separate service to deal with resource is for the controller to not know anything about the url and http method name. So what should I do?
In other words, what I want to test is that then gets called and does what I need it to do.
I guess I could probably create a separate service that gets called in then and do what I need to do with the model but it feels a bit overkill if all I want to do is, for example, set one field to null depending on a simple condition.
You are correct, you shouldn't have to use $httpBackend unless you are using $http in the controller you are testing.
As you wrote, the controller shouldn't need to know anything about the implementation of Service. What the controller knows is that Service has a get method that returns an object with a $promise property that is a promise.
What you want to do is to use a fake implementation of Service in your test. There are multiple ways to do this via mocks, spies, stubs etc, depending on your use case and which testing framework(s) you are using.
One way is to create a fake implementation like this:
var Service = {
get: function() {
deferred = $q.defer();
return {
$promise: deferred.promise
};
}
};
You want to be able to access deferred from the tests, so you can either resolve or reject the promise based on what you want to test.
Full setup:
var $rootScope,
scope,
createController,
$q,
deferred;
var Service = {
get: function() {
deferred = $q.defer();
return {
$promise: deferred.promise
};
}
};
beforeEach(function() {
module('App');
inject(function(_$rootScope_, $controller, _$q_) {
$rootScope = _$rootScope_;
scope = $rootScope.$new();
createController = function() {
$controller('MyController', {
$scope: scope,
Service: Service
});
};
$q = _$q_;
});
});
Controller implementation:
app.controller('MyController', function($scope, Service) {
$scope.property = false;
$scope.model = Service.get();
$scope.model.$promise.then(function(data) {
if (data) {
$scope.property = true;
}
});
});
You can then spy on the fake implementation to assert that it is called correctly.
Example with Jasmine:
spyOn(Service, 'get').and.callThrough();
You need and.callThrough() or the call will be interrupted and your fake implementation will not be used.
You now have full control by manually creating the controller, resolving the promise and triggering the digest loop and can test the different states:
it('Should work', function() {
spyOn(Service, 'get').and.callThrough();
expect(Service.get).not.toHaveBeenCalled();
createController();
expect(Service.get).toHaveBeenCalled();
expect(scope.property).toBeFalsy();
deferred.resolve('some data');
$rootScope.$digest();
expect(scope.property).toBeTruthy();
});
Demo: http://plnkr.co/edit/th2pLWdVa8AZWOyecWOF?p=preview

Unable to use httpBackend flush for ngMockE2E

I am trying to test my controller using jasmine. Basically, when the controller is created it will call a service to make http request. I am using httpBackend to get the fake data. When I try to run the test I always get the error "No pending request to flush". If I remove the httpBackend.flush() then the test fails because controller.data.name is undefined. Can anyone know why it happens like that? Thanks.
The code for the module is here:
var myModule = angular.module('myModule', ['ngMockE2E']);
myModule.run(function($httpBackend){
$httpBackend.whenGET('/Person?content=Manager').respond(function (){
var response = {'name':'Bob','age':'43'}
return [200,response];
})
});
The code for the service:
myModule.factory('myService',function($http){
return {
getData: function(position){
return $http.get('/Person?content='+position);
}
}
});
The code for controller is:
myModule.controller('myController',function(xrefService){
var _this = this;
_this.data ={};
_this.getData = function(position){
myService.getData(position).then(function(response){
_this.data = response.data
});
}
_this.getData("Manager");
})
The code to test the controller is:
describe("Test Controller",function(){
var controller,httpBackend,createController;
beforeEach(module('myModule'));
beforeEach(inject(function($controller,$httpBackend){
createController = function(){
return $controller('myController');
}
httpBackend = $httpBackend;
}));
it("should return data",function(){
controller = createController();
httpBackend.flush();
expect(controller.data.name).toEqual("Bob");
});
})
The angular documentation says the following about $httpbackend for ngMockE2E:
Additionally, we don't want to manually have to flush mocked out
requests like we do during unit testing. For this reason the e2e
$httpBackend flushes mocked out requests automatically, closely
simulating the behavior of the XMLHttpRequest object.
So, short answer: it doesn't exist and you don't need it.
you are using $httpBackend.whenGET inside "The code for the module"
you should be using $httpBackend inside the test code as follows ...
it("should return data",function(){
$httpBackend.expectGET('/Person?content=Manager').respond(function (){
var response = {'name':'Bob','age':'43'}
return [200,response];
})
controller = createController();
httpBackend.flush();
expect(controller.data.name).toEqual("Bob");
});
also i would advise using expectGET instead of whenGET.
With whenGET you are saying if the request is made then response like so.
With expectGET you are saying ... a request will be made, when it is made respond like so, if the request is not made then fail the test.
PS if you put some console.log statements inside your controller code then you should see these log statements when you run your test suite. If not then you know your controller code is not even being hit.
also use ..
afterEach(function () {
httpBackend.verifyNoOutstandingExpectation();
httpBackend.verifyNoOutstandingRequest();
});
which will force test failure if expectations were not met.

$httpBackend.flush() method throws Error: [$rootScope:infdig] 10 $digest() iterations reached. Aborting

I am trying to unit test my AngularJS application using Karma and Jasmine. I want to mock the $http service. For that, I am using the $httpBackend method. Below is my service that I want to test:
angular.module('MyModule').factory('MyService', function($http, $log, $parse, $q, $timeout, $filter, MyOtherService1, MyOtherService2){
var service = {};
service.getSomething = function(id){
return $http.get('/somePath/subpath/' + id);
}
});
My unit test for this service is:
describe("myTest", function(){
var myService, $httpBackend, scope, mockMyOtherService1, mockMyOtherService2;
var myResponse =
{
foo:'bar'
};
beforeEach(module("MyModule"));
beforeEach(inject(function(_MyService_, $injector){
$httpBackend = $injector.get('$httpBackend');
myService = _MyService_;
scope = $injector.get('$rootScope').$new();
mockMyOtherService1 = $injector.get('MyOtherService1');
mockMyOtherService2 = $injector.get('MyOtherService2');
}));
beforeEach(function(){
//To bypass dependent requests
$httpBackend.whenGET(/\.html$/).respond(200,'');
});
//If I uncomment the below afterEach block, the same error is shown at next line.
/*afterEach(function() {
$httpBackend.verifyNoOutstandingExpectation();
$httpBackend.verifyNoOutstandingRequest();
});*/
//This test passes successfully
it("should check if service is instantiated", function () {
expect(myService).toBeDefined();
});
//This test passes successfully
it("should expect dependencies to be instantiated", function(){
expect($httpBackend).toBeDefined();
});
//The problem is in this test
it("should get the getSomething with the provided ID", function() {
$httpBackend.whenGET('/somePath/subpath/my_123').respond(200,myResponse);
var deferredResponse = myService.getSomething('my_123');
//The error is shown in next line.
$httpBackend.flush();
//If I comment the $httpBackend.flush(), in the next line, the $$state in deferredResponse shows that the Object that I responded with is not set i.e. it does not matches the 'myResponse'.
expect(deferredResponse).toEqual(myResponse);
});
});
This is an emergency problem and I need help regarding the same as soon as possible. I will be very grateful for your answer.
The problem was I needed to inject $location in my spec files even though they are not injected in the services. After injection, all worked well! Hope this helps someone who gets stuck in the same situation.
You will get a promise from your service. So change your test code to:
//The problem is in this test
it("should get the getSomething with the provided ID", function (done) {
$httpBackend.expectGET('/somePath/subpath/my_123').respond(200,myResponse);
var deferredResponse = myService.getSomething('my_123');
deferredResponse.then(function (value) {
expect(value.data).toEqual(myResponse);
}).finally(done);
$httpBackend.flush();
});
I've recently had this problem when updating a project from Angular 1.2 to 1.4. The test code looked something like:
it('should call /something', function(){
httpBackend.expectGET('/something').respond(200);
scope.doSomething();
httpBackend.flush();
});
The error was the infdig past 10 iterations. It was caused by invoking the .flush() method. I figured out this is seemingly because there were no pending promises created within doSomething().
Once I added a promise somewhere within doSomething() or inner methods, the infdig problem went away.
I suspect - and this is 100% speculation so don't let it influence your development - this is because httpBackend does some trickery to wait for promises, which maybe involves digesting repeatedly until there's a change. Since there's no promises, there's no changes - infinite digest.

AngularJS testing callbacks to then functions within services

I'm looking to write a Jasmine unit test which executes a callback function passed to a then function. This then function is chained to a call to the AngularJS $http service, and it's inside a custom service. Here's the code I'm working with:
app.service('myService', function($rootScope, $http) {
var service = this;
var url = 'http://api.example.com/api/v1/resources';
service.resources = {
current: []
};
service.insertResource = function (resource) {
return $http.post(url, resource).then(function(response){
$rootScope.$broadcast('resources:updated', service.resources.current);
return response;
});
};
});
Here's my attempt to write a test which executes this callback, but to no avail:
describe('resource service', function() {
beforeEach(angular.mock.module('myapp'));
var resourceService;
beforeEach(inject(function(_resourceService_) {
resourceService = _resourceService_;
}));
it('should insert resources', function() {
resourceService.insertResource({});
});
});
There are several approaches you could take:
Use $httpBackend.expectPOST
Use $httpBackend.whenPOST
Move the code in the callback to a named function (not an anonymous one) and write a test for this function. I sometimes take this route b/c I don't want the trouble of writing tests with $httpBackend. I only test the callback function, I don't test that my service is calling the callback. If you can live w/that it's much simpler approach.
Check the documentation for $httpBackend for details. Here's a simple example:
describe('resource service', function() {
beforeEach(angular.mock.module('myapp'));
var resourceService, $httpBackend;
beforeEach(inject(function($injector) {
resourceService = $injector.get('resourceService');
$httpBackend = $injector.get('$httpBackend');
}));
afterEach(function() {
// tests will fail if expected HTTP requests are not made
$httpBackend.verifyNoOutstandingRequests();
// tests will fail if any unexpected HTTP requests are made
$httpBackened.verifyNoOutstandingExpectations();
});
it('should insert resources', function() {
var data: { foo: 1 }; // whatever you are posting
// make an assertion that you expect this POST to happen
// the response can be an object or even a numeric HTTP status code (or both)
$httpBackend.expectPOST('http://api.example.com/api/v1/resources', data).respond({});
// trigger the POST
resourceService.insertResource({});
// This causes $httpBackend to trigger the success/failure callback
// It's how you workaround the asynchronous nature of HTTP requests
// in a synchronous way
$httpBackend.flush();
// now do something to confirm the resource was inserted by the callback
});
});

AngularJS "No pending request to flush" while unit testing a controller with a $resource

I am writing unit tests for a controller. This controller has a $resource service injected :
function controller($scope, Service) {
Service.get(function(result){
// do stuff with the result, not relevant here
}
}
The service is defined like this :
angular.module('so').factory('Service', ['$resource', service]);
function service($resource) {
return $resource('/url', null, {
get: { method: 'POST', params: {}, isArray: false}
});
}
My Jasmine unit test is the following :
describe("Controller", function(){
var $httpBackend;
beforeEach(function() {
module('so');
inject(function( _$httpBackend_) {
$httpBackend = _$httpBackend_;
});
});
it('should have done stuff irrelevant to the question', function() {
var $injector = angular.injector('so'),
$scope = $injector.get('$rootScope'),
$httpBackend
.whenPOST('/url')
.respond ([]);
// controller needs to be defined here and not in the beforeEach as there
// are more parameters passed to it, depending on the test
var controller = $injector.get('$controller')('controller', { "$scope": $scope });
$httpBackend.flush();
// then here the actual test resolution, also irrelevant
});
});
I get an error when running the test :
Error: No pending request to flush ! in file:///path/to/angular-mock.js (line 1453)
I added a console.log() in the callback from Service.get() and indeed, it is not called (everything outside of the callback is of course called). Also tried to add a scope digest if not phased after controller creation in the unit test, as I saw suggested in an other question, with no luck.
I know that I can mock that in some other ways, but using $httpBackend seems the perfect solution for the test : mocking the webserver and the data received.
I'm using AngularJS 1.2.16 (can't upgrade to 1.3.*, IE 8 compatibility required). I first used 1.2.13 and updated to check if it would solve the issue, without any luck.
That was an injection issue that was solved by changing the test from
it('should have done stuff irrelevant to the question', function() {
var $injector = angular.injector('so'),
$scope = $injector.get('$rootScope'),
$httpBackend
.whenPOST('/url')
.respond ([]);
// controller needs to be defined here and not in the beforeEach as there
// are more parameters passed to it, depending on the test
var controller = $injector.get('$controller')('controller', { "$scope": $scope });
$httpBackend.flush();
// then here the actual test resolution, also irrelevant
});
To:
it('should have done stuff irrelevant to the question', inject(function(Service) {
// edited lines because they did not change
var controller = $injector.get('$controller')('controller', { "$scope": $scope, "Service": Service });
// edited lines because they did not change
}));
So basicaly, adding the inject() in the test function and passing the service to the controller "manually".
I found the issue, that's great, but I don't really understand why it doesn't work. Also, I tried this right after finding the solution :
it('should have done stuff irrelevant to the question', inject(function() {
// edited lines because they did not change
var Service = $injector.get('Service'),
var controller = $injector.get('$controller')('controller', { "$scope": $scope, "Service": Service });
// edited lines because they did not change
}));
but this fail again, with the same "no pending request" error. I'm guessing that's some sort of racing issue, where my service can't get the proper $httpBackend to be injected when it's created afterwards, but I don't really understand why this occurs. If anybody can enlighten me... I'll be grateful.

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