How to unit test an asynchronus factory which uses another factory in AngularJS?

Question

I am trying to write some unit tests for my databaseContacts factory, and I am very lost as to how to actually write them, as there are a number of complications.

Here is the factory I want to test:

 .factory('databaseContacts', 
   function (getDatabaseContactsFromDB ){

     return {
       getContacts: function(){
         var dbContacts = getDatabaseContactsFromDB.query();
         return dbContacts.$promise.then(function(result){
           return result;
         });
       },
       removeContact: function (contact){
         getDatabaseContactsFromDB.remove(contact);
       },
       addContact: function (contact){
         var addedContact =  getDatabaseContactsFromDB.save(contact);
         return addedContact.$promise.then(function(result){
           return result;
         });
       }
     };
 })

And here is getDatabaseContactsFromDB:

 .factory('getDatabaseContactsFromDB', function ($resource){
   return $resource('http://localhost:8000/contacts/');
 })

Here's my attempt at a setup for my test:

 describe( 'databaseContacts service', function(){
   var databaseContacts, httpBackend;
   beforeEach(function() {
     module('App.contacts');

     inject (function ($httpBackend, _databaseContacts_){
       databaseContacts = _databaseContacts_;
       httpBackend = $httpBackend;
     });
   });
   afterEach(function(){
     httpBackend.verifyNoOutstandingExpectation();
     httpBackend.verifyNoOutstandingRequest();
   });

   it ('should get database contacts', function (){
     //somehow call databaseContacts.getContacts() and nicely mock the return data
   });

 });

I don't have a grasp on how one could mock all of these asynchronous calls, and I haven't been able to find any examples on the web that I can translate over to my scenario. I also feel like my code is further complicated by having a factory being called within another factory. Any help would be appreciated.

Answer 1

When you call, let's say getContacts, you'll have to flush $httpBackend and you have to mock response for that URL so something like this:

var storedData;
databaseContacts.getContacts().then(function(data) {
   storedData = data;
});
httpBackend.expect('GET', 'http://localhost:8000/contacts/').respond(<mocked_json_here>)
httpBackend.flush()
expect(storedData).toBeDefined()