feat(router): exposes the fixture of the RouterTestingHarness (#5…

…0280)

The component exposed by the fixture is not important thus marked as `unknown`.

Exposing the fixture of the `RouterTestingHarness` allows to use the methods & properties of that fixture and makes it compatible with testing libraries relying on `ComponentFixture`

Fixes #48855

PR Close #50280

goldens/public-api/router/testing/index.md

@@ -6,6 +6,7 @@
 
 import { ChildrenOutletContexts } from '@angular/router';
 import { Compiler } from '@angular/core';
+import { ComponentFixture } from '@angular/core/testing';
 import { DebugElement } from '@angular/core';
 import { ExtraOptions } from '@angular/router';
 import * as i0 from '@angular/core';
@@ -26,6 +27,7 @@ import { UrlSerializer } from '@angular/router';
 export class RouterTestingHarness {
     static create(initialUrl?: string): Promise<RouterTestingHarness>;
     detectChanges(): void;
+    readonly fixture: ComponentFixture<unknown>;
     navigateByUrl(url: string): Promise<null | {}>;
     navigateByUrl<T>(url: string, requiredRoutedComponentType: Type<T>): Promise<T>;
     get routeDebugElement(): DebugElement | null;

packages/router/testing/src/router_testing_harness.ts

@@ -68,16 +68,23 @@ export class RouterTestingHarness {
     return harness;
   }
 
+  /**
+   * Fixture of the root component of the RouterTestingHarness
+   */
+  public readonly fixture: ComponentFixture<unknown>;
+
   /** @internal */
-  constructor(private readonly fixture: ComponentFixture<RootCmp>) {}
+  constructor(fixture: ComponentFixture<unknown>) {
+    this.fixture = fixture;
+  }
 
   /** Instructs the root fixture to run change detection. */
   detectChanges(): void {
     this.fixture.detectChanges();
   }
   /** The `DebugElement` of the `RouterOutlet` component. `null` if the outlet is not activated. */
   get routeDebugElement(): DebugElement|null {
-    const outlet = this.fixture.componentInstance.outlet;
+    const outlet = (this.fixture.componentInstance as RootCmp).outlet;
     if (!outlet || !outlet.isActivated) {
       return null;
     }
@@ -136,7 +143,7 @@ export class RouterTestingHarness {
     await router.navigateByUrl(url);
     await redirectTrackingPromise;
     this.fixture.detectChanges();
-    const outlet = this.fixture.componentInstance.outlet;
+    const outlet = (this.fixture.componentInstance as RootCmp).outlet;
     // The outlet might not be activated if the user is testing a navigation for a guard that
     // rejects
     if (outlet && outlet.isActivated && outlet.activatedRoute.component) {