Test HTTP client usage as well

Author: Dave Syer

src/main/client/src/app/app.component.spec.ts

@@ -1,6 +1,6 @@
 import { TestBed, async } from '@angular/core/testing';
 import { AppComponent } from './app.component';
-import { HttpClientTestingModule } from '@angular/common/http/testing'
+import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing'
 describe('AppComponent', () => {
   beforeEach(async(() => {
     TestBed.configureTestingModule({
@@ -26,4 +26,11 @@ describe('AppComponent', () => {
     const compiled = fixture.debugElement.nativeElement;
     expect(compiled.querySelector('h1').textContent).toContain('Welcome Demo!');
   }));
+  it('should fetch data from backend', async(() => {
+    const http = TestBed.get(HttpTestingController);
+    const fixture = TestBed.createComponent(AppComponent);
+    const app = fixture.debugElement.componentInstance;
+    http.expectOne('resource').flush({id:'XYZ',content:'Hello'});
+    expect(app.data.content).toContain('Hello');
+  }));
 });