title: error:NullInjectorError: No provider for Router
body: <p>I have to test one component  and get this error NullInjectorError: R3InjectorError(DynamicTestModule)[AuthenticationService -&gt; Router -&gt; Router]:
  NullInjectorError: No provider for Router!**&quot;
  The component I'm testing have two dependencies and I don't know hot to provide both them in the test with testbed
  <strong>gallery.component.ts</strong></p>
  <pre><code>constructor( private authService:AuthenticationService, private iterableDiffers: IterableDiffers){
          this.iterableDiffer = iterableDiffers.find([]).create(null);
      }
  </code></pre>
  <p><strong>gallery.component.spec.ts</strong></p>
  <pre><code>describe('GalleryComponent', () =&gt; {
  
      let component: GalleryComponent;
      let fixture: ComponentFixture&lt;GalleryComponent&gt;
      let authServiceMock: AuthenticationService
      let iterableDifferMock: IterableDiffers
  
      beforeEach(() =&gt; {
          TestBed.configureTestingModule({
          providers:[GalleryComponent, {provide:AuthenticationService}, {provide:IterableDiffers}]
      })
          
  
          fixture = TestBed.createComponent(GalleryComponent);
          component = fixture.componentInstance;
  
          authServiceMock = TestBed.inject(AuthenticationService)
      })
  ...
  </code></pre>
  <p>how to provide both dependencies?<br />
  I read the Angular DOC and I didn't find the solution, I sew other asks on SO but without find solutions.<br />
  Thanks</p>