improve: tests

src/app/app.component.spec.ts

@@ -1,31 +1,50 @@
 import type { ComponentFixture } from '@angular/core/testing';
 import { TestBed } from '@angular/core/testing';
+import { provideRouter } from '@angular/router';
 
 import { AppComponent } from './app.component';
 
 describe('AppComponent', (): void => {
+  let fixture: ComponentFixture<AppComponent>;
+  let component: AppComponent;
+
   beforeEach(async (): Promise<void> => {
     await TestBed.configureTestingModule({
       imports: [AppComponent],
+      providers: [provideRouter([])],
     }).compileComponents();
-  });
 
-  it('should create the app', (): void => {
-    const fixture: ComponentFixture<AppComponent> = TestBed.createComponent(AppComponent);
-    const app: AppComponent = fixture.componentInstance;
-    expect(app).toBeTruthy();
-  });
-
-  it(`should have the 'Angular-Portfolio-Seite' title`, (): void => {
-    const fixture: ComponentFixture<AppComponent> = TestBed.createComponent(AppComponent);
-    const app: AppComponent = fixture.componentInstance;
-    expect(app.title).toEqual('Angular-Portfolio-Seite');
-  });
-
-  it('should render title', (): void => {
-    const fixture: ComponentFixture<AppComponent> = TestBed.createComponent(AppComponent);
+    fixture = TestBed.createComponent(AppComponent);
+    component = fixture.componentInstance;
     fixture.detectChanges();
-    const compiled = fixture.nativeElement as HTMLElement;
-    expect(compiled.querySelector('h1')?.textContent).toContain('Hello, Angular-Portfolio-Seite');
+  });
+
+  it('should create', (): void => {
+    expect(component).toBeTruthy();
+  });
+
+  it('should have title "Lechner Julian"', (): void => {
+    expect(component.title).toBe('Lechner Julian');
+  });
+
+  it('should render a router-outlet element', (): void => {
+    const el = fixture.nativeElement as HTMLElement;
+    expect(el.querySelector('router-outlet')).not.toBeNull();
+  });
+
+  it('should not render any additional root elements besides router-outlet', (): void => {
+    const el = fixture.nativeElement as HTMLElement;
+    const children = Array.from(el.children);
+    expect(children.length).toBe(1);
+    expect(children[0].tagName.toLowerCase()).toBe('router-outlet');
+  });
+
+  describe('Performance', (): void => {
+    it('should create and run initial change detection within 100 ms', (): void => {
+      const start = performance.now();
+      const f = TestBed.createComponent(AppComponent);
+      f.detectChanges();
+      expect(performance.now() - start).toBeLessThan(100);
+    });
   });
 });