How do I unit test an AngularJS controller that re

问题:

In my controller, I have:

  $scope.index = function() {
    CompanyService.initialized.then(function() {
      var company_id = CompanyService.getCompany()._id;
      LocationService.list(company_id, $routeParams.location_parent_id).then(function(response) {
        if(response.data.status === 'ok') {
          $scope.locations = response.data.locations;
          $scope.current_location = response.data.location || null;
        }
      });
    });
  }

So it should get the LocationService list and the test is as follows:

it('should get locations', function() {
  $httpBackend.when('GET', '/api/v1/location/list').respond({status: 'ok', locations: ['loc1', 'loc2']})
  $scope.index();
  expect($scope.locations.length).toEqual(2);

However, this never happens, because CompanyService has a promise that never gets resolved in the unit test. How do I either mock the returned promise of CompanyService or bypass it?

回答1:

Simply mock the call using createSpyObj method from Jasmine:

describe('one test', function(){

 var deferred, CompanyService, $scope;

 beforeEach(inject(function ($q, $rootScope, $controller) {
  params = {
        $scope: $rootScope.$new(),
        CompanyService = jasmine.createSpyObj('CompanyService', ['initialized'])
  }
  params.CompanyService.initialized.andCallFake(function () {
      deferred = $q.defer();
      return deferred.promise;  //will fake to return a promise, in order to reach it inside the test
    });
  $controller('YourController', params);
 });

 it('my test', function(){
     deferred.resolve({}); //empty object returned for the sample but you can set what you need to be returned
     $scope.$digest(); //important in order to resolve the promise
    //at this time, the promise is resolved! so your logic to test can be placed here
 });
});

回答2:

Short answer: Add $scope.$apply(); after calling $scope.$index();.

Long answer: Your problem is probably due to the way $q propagates promises resolution. Indeed resolution only happens when $digest is performed. I don't know why $digest is not performed during tests whereas it is during regular use, but this solution is suggested anyway in the Angular documentation here: https://docs.angularjs.org/api/ng/service/$q .

What's more you could directly use $scope.$digest(); in your case instead of $scope.$apply(); since $apply is only a wrapper that runs any function passed to it before calling $digest.