Angular 2 unit testing - getting error Failed to load 'ng:///DynamicTestModule/module.ngfactory.js'

Question

I have angular 2 webpack application, all webpack,karma configuration created as per angular.io webpack guide. I am not using aot. I am writing jasmine unit test spec to te

Answer 1

I ran into this issue myself yesterday. The problem was that I had an Input() property on my component class that I wasn't setting in the test. So for example, in my-component.ts:

@Component({
  selector: 'my-component'
})
export class MyComponent {
  @Input() title: string;
}

and my-component.spec.ts:

beforeEach(() => {
  fixture = TestBed.createComponent(MyComponent);
  component = fixture.componentInstance;
  component.title = 'Hello there!' // <-- this is required!
  fixture.detectChanges();
});

Or you could provide a default value in the component somewhere. Either way, the test will crash if any inputs are not set and you'll get that unintuitive error.

Note: Running ng test -sm=false will give the actual error message causing the problem. Credit: https://stackoverflow.com/a/45802115/61311

Answer 2

running tests with --sourcemaps=false will not fail Karma silently but give you some detail about the error instead.

Answer 3

I just had this issue as well. It turned out to be a simple null reference error in my component in one of my *ngIf checks.

I would suggest running ng serve and checking the component is working in the browser without any errors, or simply run ng test --source-map=false to get a more useful error message.

Answer 4

I had the same error when I accessed a variable of an undefined object.

Example:

Component:

soemthing = {}

Template:

<demo-something [someinput]="something.anotherthing.data"> ...

So something was defined, anotherthing was undefined and data could therefor not be accessed.

Very annoying error and as far as I could tell not in the list yet :)