Promise is not being handled

问题

I am writing a unit test for my Angular application using Jasmine with a mock service. However, the promise I am trying to run is not working.

Here's the service:

CreateItemController = $controller('CreateItemController', {
    ItemService: {

        createItem: function(data) {
            console.log('Service running');
            var defer = $q.defer();
            defer.resolve('1');
            return defer.promise;   
        }

The test:

it('should create an item', function() {

    var created = false;
    $scope.createItem().then(function(response) {
        // This is not being run                
        console.log("We got through");
        created = true;
    });

    expect(created).toBe(true);

})

And finally the actual function:

    $scope.createItem = function() {
        var postData = {
            name: 'Jeans'
        };

        return ItemService.createItem(postData).then(function(response) {
            // This is not being run                
            console.log('Promise recieved');
        });
    }

What am I doing wrong?

回答1:

You should mock the $q service so that the resolution of the promise is not async anymore in your test.

There is no point testing the $q service itself, you only want to test your custom logic.

  describe('controller: CreateItemController', function () {
    var subject, $scope;
    beforeEach(module('myModule'));
    beforeEach(inject(function ($rootScope, $controller, $q) {
      $scope = $rootScope.$new();

      subject = $controller('CreateItemController', {
        $scope: $scope,
        ItemService: {
          createItem: function () {
            var defer = $q.defer();
            spyOn(defer.promise, 'then').andCallFake(function (callback) {
              callback();
              return this;
            });
            return defer.promise;
          }
        }
      });
    }));

    it('should create an item', function () {
      var created = false;
      var subject = $scope.createItem().then(function () {
        created = true;
      });

      //deferred.resolve('1'); // useless as our callbacks are called as soon as they are registered

      expect(created).toEqual(true);
    });
  });

If you want to keep the delay though, you could call $scope.$apply() after resolving the deferred object as follow:

  describe('controlle: stack overflow', function () {
    var subject, $scope, deferred;
    beforeEach(module('myModule'));
    beforeEach(inject(function ($rootScope, $controller, $q) {
      $scope = $rootScope.$new();

      subject = $controller('CreateItemController', {
        $scope: $scope,
        ItemService: {
        createItem: function () {
            deferred = $q.defer();
            return deferred.promise;
          }
        }
      });
    }));

    it('should create an item', function () {
      var expected = {
        one: false,
        two: false,
      };
      var subject = $scope.createItem();
      subject.then(function () {
        expected.one = true;
      }).then(function () {
        expected.two = true;
      });

      deferred.resolve();
      expect(expected.one).toEqual(false);
      expect(expected.two).toEqual(false);

      $scope.$apply();

      expect(expected.one).toEqual(true);
      expect(expected.two).toEqual(true);
    });
  });
});

来源：https://stackoverflow.com/questions/24264161/promise-is-not-being-handled

标签

javascript

angularjs

unit-testing

testing

jasmine