Can't test POST $http request with $httpBackend

Question

Trying to cover http requests of my app by unit tests. I use Jasmine and Karma and step by step write my code using this tutorial: https://docs.angularjs.org/api/ngMock/service/ $httpBackend. But I get an error:

Error: No pending request to flush !
        at Function.$httpBackend.flush (eval at <anonymous> (app/index.js:105:1), <anonymous>:1839:41)
        at Object.eval (eval at <anonymous> (app/index.js:137:1), <anonymous>:37:20)

This answer Unit testing AngularJS controller with $httpBackend is so popular for my problem but when I move const controller = createController(); down - I've got another one error: Error: Unsatisfied requests: POST http://loalhost:5000/register .

Where is my mistake? What I implemented wrong?

My unit test:

beforeEach(window.module(ngModule.name));

let $httpBackend, $rootScope, $controller, $scope, createController;

beforeEach(
  inject($injector => {
    $httpBackend = $injector.get('$httpBackend');
    $controller = $injector.get('$controller');
    $rootScope = $injector.get('$rootScope');
    $scope = $rootScope.$new();

    createController = () =>
      $controller('RegistrationController', { $scope });
  })
);

afterEach(() => {
  $httpBackend.verifyNoOutstandingExpectation();
  $httpBackend.verifyNoOutstandingRequest();
});

it('should successfully register user', () => {
  const controller = createController();
  $httpBackend.flush();
  $httpBackend.expectPOST('http://localhost:5000/register').respond();
  $scope.next('hello@gmail.com', '123456');
  $httpBackend.flush();
});

Block of code from the controller:

  $scope.status;
  $scope.isFetching = false;

  const handleResponse = response => {
    $scope.status = response.status;
    $scope.isFetching = false;
  };

  $scope.next = (email, password) => {
    $scope.isFetching = true;
    $http
      .post('http://localhost:5000/register', { email, password })
      .then(response => handleResponse(response))
      .catch(response => handleResponse(response));
  };

UPD

I also tried to add before each $httpBackend.flush() this one (like here Angularjs testing (Jasmine) - $http returning 'No pending request to flush' ):

if(!$rootScope.$$phase) {
    $rootScope.$apply();
}

But anyway, nothing change.

Answer 1

You call $httpBackend.flush() after controller creation here:

it('should successfully register user', () => {
  const controller = createController();
  $httpBackend.flush(); //<-- this is not necessary if controller creation doesn't involve $http calls
  $httpBackend.expectPOST('http://loalhost:5000/register').respond();
  $scope.next('hello@gmail.com', '123456');
  $httpBackend.flush();
});

Should be like this:

it('should successfully register user', () => {
  const controller = createController();
  $httpBackend.expectPOST('http://loalhost:5000/register').respond();
  $scope.next('hello@gmail.com', '123456');
  $httpBackend.flush();
});