Angular 4 Unit test error - Failed to execute 'send' on 'XMLHttpRequest': Failed to load 'ng:///DynamicTestModule/LoginComponent.ngfactory.js'

Question

I am writing some unit tests for my component and i am getting this cryptic error message. I found a similar question at Angular 2 unit testing - getting error Failed to load &#

Answer 1

I encountered the same issue using angular-cli 6, so to get the right error message one should use the following:

ng test --source-map=false

Maybe it will help someone :) .

Answer 2

I just ran into this error and the problem was my mocks. In the component.ngOnInit i used this.route.paramMap.subscribe(...) where route is an ActivatedRoute instance

In my test i provided a mock service like this :

providers: [
    { provide: ActivatedRoute, useValue: { snapshot: { params: { id: 1 } } } }
]

And in fact i missed to mock the paramMap method

Then i fix it adding a paramMap properties like this

providers: [
    { provide: ActivatedRoute, useValue: { snapshot: { params: { id: 1 } }, paramMap: Observable.of({get: () => 1}) } }
]

Then i don't have anymore this stupid error.

So for you, i expect the class SessionServiceStub to be incomplete or erroneous. Does it get a login method that return an Observable ?

If it's not the problem you can check the NotificationServiceStub

You should use a debugger (with Webstorm it's easy to debug step-by-step) to help you.

Answer 3

Been chasing this for hours. Finally discovered that the problem was simply that I had imported HttpClientModule, but not HttpClient:

import { HttpClient, HttpClientModule } from '@angular/common/http';

All those CORS errors, and '[Script Loader]', DOMException{stack: 'Error: Failed to execute 'send' on 'XMLHttpRequest' stuff, and it came down to just not having HttpClient!

Answer 4

This is a problem with the Angular Cli version 1.2.2 or newer. Run your test with --sourcemaps=false and you will get the right error messages.

In Angular 4-5

• ng test --sourcemaps=false
  

  or

• ng test -sm=false
  

In Angular 6+

• ng test --source-map=false
  

See details here: https://github.com/angular/angular-cli/issues/7296