Angular tests failing with Failed to execute 'send' on 'XMLHttpRequest'

I had the same issue using angualar cli 6, I have used this tag to get the right error message :

ng test --source-map=false

Maybe it will help someone :) .

For my case there was a mock data problem and in case of Array, I was returning string from the mock.

someApi = fixture.debugElement.injector.get(SomeApi);
spyOn(someApi, 'someMethod')
  .and.returnValue(Observable.of('this is not a string but array'));

The error message is really distracting and was not telling the actual error. Running ng test --source=false pointed the correct error and line, and helped me to fix it quickly.

Many time it happens when you mock data is incomplete or incorrect.

You can either set input() property to default value in component.ts

@Input() tableColumns: Array<any> = [];  
@Input() pageObj: any = '';

OR

Modify your component.spec.ts file in following way,

beforeEach(() => {  
   fixture = TestBed.createComponent(MyComponent);  
   component = fixture.componentInstance;  
   component.tableColumns = [];  
   component.pageObj = '';  
   fixture.detectChanges();  
});

As suggested above here: https://stackoverflow.com/a/45570571/7085047 my problem was in my ngOnInit. I was calling a mock swagger-generated REST controller proxy. It was returning null, and I was subscribing to that null, which doesn't work...

The error came back:

Failed to load ng:///DynamicTestModule/MockNodeDashboardComponent_Host.ngfactory.js: Cross origin requests are only supported for protocol schemes: http, data, chrome, chrome-extension, https.

I fixed the issue using ts-mockito: https://github.com/NagRock/ts-mockito

I added code to create a mock instance like this:

import { mock, instance, when } from 'ts-mockito';
import { Observable } from 'rxjs/Observable';
import { Observer } from 'rxjs/Observer';
import { MockScenario } from './vcmts-api-client/model/MockScenario';

const MockVcmtsnodemockresourceApi: VcmtsnodemockresourceApi = mock(VcmtsnodemockresourceApi);
const obs = Observable.create((observer: Observer<MockScenario[]>) => {
  observer.next(new Array<MockScenario>());
  observer.complete();
});
when(MockVcmtsnodemockresourceApi.getMockScenariosUsingGET()).thenReturn(obs);
const instanceMockVcmtsnodemockresourceApi: VcmtsnodemockresourceApi = instance(MockVcmtsnodemockresourceApi);

And then added the instance to the test's providers array like this:

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      ...
      providers: [
        ...
        { provide: VcmtsnodemockresourceApi, useValue: instanceMockVcmtsnodemockresourceApi },
        ...
      ]        
    }).compileComponents();
  }));

I faced the same issue and I've found out that to fix it you have to set your inputs for the component in the method beforeEach as shown below:

beforeEach(() => {
    fixture = TestBed.createComponent(CellComponent );
    cmp = fixture.debugElement.componentInstance;
    cmp.dep = '';
    cmp.embedded = false;
    cmp.dashboard = false;
    fixture.detectChanges();
});

This will definitely resolve your issue.

I also had this error, which truth be told is fairly non talkative.

It was related to the HTTP calls trough my services

I use myService.ts with 2 methods

get();
getAll();

I am mocking this service : mockMyService.ts

The error was here because my component was using getAll() method that I forgot to implement in the mockMyService, so I just added the method :

private mockObjects = [
{
  'id': '1',
  'champ1': 'TECH',
  'champ2': 2,
  'champ3': 'Data bidon'
},
{
  'id': '2',
  'champ1': 'TECH',
  'champ2': 2,
  'champ3': 'Data au pif'
},
{
  'id': '3',
  'champ1': 'FUNC',
  'champ2': 3,
  'champ3': 'Data quelconque'
},
 ];

getAll(): Observable<any> {
  return Observable.of(this.mockObjects);
}

Error was gone :)

What I would be doing is:

Add console.log() s, line after line in ngOnint() and find out how far it goes , then inspect the line which it wont pass through.

Ex:

ngOnInit() {
    this.route.paramMap
        .switchMap(params => {
            this.busy = true;
            this.updateErrors(null);

            console.log(params);

            **const id = params.get('id');**
            console.log(id);

            if (id === 'new') {
                this.editMode = true;
                return Observable.of(GroupComponent.newGroup());
            }
            return this.apiService.getGroup(id);
        })
    }

This was failing on my test with the same error in this post. As shown above, I had two console.logs. First one passed thorugh , but the second one not. So I realized the issue is on line const id = params.get('id'); and I fixed it.

Hope this will help someone.