tl;dr In almost all cases, they can be used interchangeably, but using fakeAsync()/tick() combo is preferred unless you need to make an XHR call, in which case you MUST use async()/whenStable() combo, as fakeAsync() does not support XHR calls. For the most part they can be used interchangeably. I can’t think of anything off the … Read more
For testing we now create a testing module using TestBed. We can use the TestBed#configureTestingModule and pass a metadata object to it the same way we would pass to @NgModule beforeEach(() => { TestBed.configureTestingModule({ imports: [ /* modules to import */ ], providers: [ /* add providers */ ], declarations: [ /* components, directives, and … Read more
The simplest way to do this is to just use the useValue attribute and provide an Observable of the value you want to mock. RxJS < 6 import { Observable } from ‘rxjs/Observable’; import ‘rxjs/add/observable/of’; … { provide: ActivatedRoute, useValue: { params: Observable.of({id: 123}) } } RxJS >= 6 import { of } from ‘rxjs’; … Read more
async will not allow the next test to start until the async finishes all its tasks. What async does is wrap the callback in a Zone, where all asynchronous tasks (e.g. setTimeout) are tracked. Once all the asynchronous tasks are complete, then the async completes. If you have ever worked with Jasmine outside out Angular, … Read more
You can simply mock Observable throw error object like Observable.throw({status: 404})and test error block of observable. const xService = fixture.debugElement.injector.get(SomeService); const mockCall = spyOn(xService, ‘method’).and.returnValue(Observable.throw({status: 404})); Update 2019 : Since some people are lazy to read comment let me put this here : It’s a best practice to use errors for Rxjs import { throwError … Read more
Using Jest? In case anyone gets here AND you’re using Jest to test your Angular app (hopefully we’re a growing minority), you will run into this error if you are not emitting decorators (“emitDecoratorMetadata”:true). You’ll need to update your tsconfig.spec.json file so it looks like: { “extends”: “../../tsconfig.json”, “compilerOptions”: { “emitDecoratorMetadata”: true, “outDir”: “../../out-tsc/spec”, “types”: … Read more
You need to configure all the routing. For testing, rather than using the RouterModule, you can use the RouterTestingModule from @angular/router/testing, where you can set up some mock routes. You will also need to import the CommonModule from @angular/common for your *ngFor. Below is a complete passing test import { Component } from ‘@angular/core’; import … Read more