fix(router): avoid router initialization for non root components

closes #12338
closes #12814

modules/@angular/router/test/router_module.spec.ts

@@ -0,0 +1,91 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import {APP_BASE_HREF} from '@angular/common';
+import {ApplicationRef, Component, NgModule} from '@angular/core';
+import {TestBed, inject} from '@angular/core/testing';
+import {DOCUMENT} from '@angular/platform-browser';
+import {Router, RouterModule, Routes} from '@angular/router';
+
+
+@Component({selector: 'app-root', template: ''})
+export class AppRootComponent {
+}
+
+@Component({selector: 'bootstrappable-component', template: ''})
+export class BootstrappableComponent {
+}
+
+export const appRoutes: Routes = [{path: '**', redirectTo: ''}];
+
+
+@NgModule({
+  imports: [RouterModule.forRoot(appRoutes)],
+  declarations: [AppRootComponent, BootstrappableComponent],
+  entryComponents: [AppRootComponent, BootstrappableComponent],
+  providers: [{provide: APP_BASE_HREF, useValue: '/'}]
+})
+export class RouterInitTestModule {
+}
+
+
+describe('RouterModule', () => {
+  describe('RouterInitializer', () => {
+
+    beforeEach(() => { TestBed.configureTestingModule({imports: [RouterInitTestModule]}); });
+
+    beforeEach(inject([DOCUMENT], function(doc: HTMLDocument) {
+
+      const elRootApp = doc.createElement('app-root');
+      doc.body.appendChild(elRootApp);
+
+      const elBootComp = doc.createElement('bootstrappable-component');
+      doc.body.appendChild(elBootComp);
+
+    }));
+    it('should not init router navigation listeners if a non root component is bootstrapped',
+       () => {
+
+         const appRef: ApplicationRef = TestBed.get(ApplicationRef);
+         const r: Router = TestBed.get(Router);
+
+         const spy = spyOn(r, 'resetRootComponentType').and.callThrough();
+
+         appRef.bootstrap(AppRootComponent);
+         expect(r.resetRootComponentType).toHaveBeenCalled();
+
+         spy.calls.reset();
+
+         appRef.bootstrap(BootstrappableComponent);
+         expect(r.resetRootComponentType).not.toHaveBeenCalled();
+       });
+    it('should reinit router navigation listeners if a previously bootstrapped root component is destroyed',
+       (done) => {
+
+         const appRef: ApplicationRef = TestBed.get(ApplicationRef);
+         const r: Router = TestBed.get(Router);
+
+         const spy = spyOn(r, 'resetRootComponentType').and.callThrough();
+
+         const compRef = appRef.bootstrap(AppRootComponent);
+         expect(r.resetRootComponentType).toHaveBeenCalled();
+
+         spy.calls.reset();
+
+         compRef.onDestroy(() => {
+
+           appRef.bootstrap(BootstrappableComponent);
+           expect(r.resetRootComponentType).toHaveBeenCalled();
+
+           done();
+         });
+
+         compRef.destroy();
+       });
+  });
+
+});