How to test angularjs controller async behavior without using Timeout - angularjs

Question

So I have a controller like this:
angular.module('someModule').controller('someController',function(productService) {
$scope.products = [];
$scope.init = function() {
aService.fetchAll().then(function(payload) {
$scope.products = filterProducts(payload.data);
});
}
$scope.init();
function filterProducts(products) {
//for each of products filter some specific ones
return filteredProducts;
}
});
I am writing a test that will call the $scope.init() and has to verify that the products were filtered appropriately. I am mocking the $httpBackend so the code looks like this:
describe("someController", function() {
"use strict";
var $controller; //factory
var controller; //controller
var $rootScope;
var $state;
var $stateParams;
var $injector;
var $scope;
var $httpBackend;
var productService;
beforeEach(function(){
angular.mock.module("someModule")
inject(function (_$rootScope_, _$state_, _$injector_, $templateCache, _$controller_, _$stateParams_, _$httpBackend_, _productService_) {
$rootScope = _$rootScope_;
$state = _$state_;
$stateParams = _$stateParams_;
$injector = _$injector_;
$controller = _$controller_;
$httpBackend = _$httpBackend_;
productService = _productService_;
});
controller = $controller("someController", {$scope: $scope, $state: $state});
});
it("init() should filter products correctly",function(){
//Arrange
var expectedFilteredProducts = ["1","2"];
var products = ["0","1","2"];
$httpBackend.whenGET("api/products").respond(products);
//Act
$scope.init();
//Assert
setTimeout(100,function(){
expect($scope.products).toEqual(expectedFilteredProducts);
});
$httpBackend.flush();
});
});
The problem is that without the setTimeout the test doesn't pass. Is there a way to test what I am trying to do without it and without introducing complex $q/promises just for the test? As a side note productService is returning a promise $http. Thanks.
Edit: setTimeout makes test run but no assertions are happening..

Answer 1

Based on the comments, the problem was that the $httpBackend.flush() needs to be executed before the expectations. Effectively it resolves all requests it was trained to resolve (and their respective promises) so that expectations can run on completed promises.
It is also a good idea to use $httpBackend.verifyNoOutstandingExpectation() / $httpBackend.verifyNoOutstandingRequest() after the tests.
Also note that the controller has already called scope.init(), so calling it again in the test is redundant - and may even cause failures depending on the exact case.
Also for the setTimeout running but not asserting anything: Using it in a spec makes this spec asynchronous. You will have to define the spec with the done callback and call it from the asynchronous code, when the test is really finished, as:
it("init() should filter products correctly",function(done) {
...
//Assert
setTimeout(100, function() {
...
done();
});
});
Note again that Angular mocks provide ways to avoid using setTimeout for 99.9% of the time, even the $interval/$timeout services are properly mocked!