how to test a controller that uses a promise to call a remote service

controller-promises-unit-test-js

var mockFooService,
    sut;

describe('FooController tests', function () {

	beforeEach(function($q, $controller){
	 	mockFooService = {
			bar: function() {
				return $q.reject({ data: { message: 'Error message' } });
			}
		};
		
		var $scope = {};
		
		sut = $controller('FooController', { $scope: $scope, fooService: mockFooService });
	});

	it('callBar() should call onBarError() if an error is thrown', function () {
		spyOn(sut, 'onBarError').andCallThrough();

		scope.callBar();
		
		scope.$apply(); // without the promise will not be evaluated

		expect(sut.onBarError).toHaveBeenCalled();
	});
});