Stubbing out Angular Services in Cypress

Stubbing out Angular Services in Cypress

21 May 2024 Stephan Petzl Leave a comment Tech-Help

Running end-to-end tests on an Angular web application using Cypress can be challenging, especially when dealing with third-party authentication providers like Cognito. This guide will help you effectively stub out Angular services, ensuring your tests run smoothly.

Understanding the Challenge

In an Angular application, services are often used to handle authentication. For instance, you might have a service like this:

  providedIn: 'root'
export class AuthenticationService {
  // Authentication methods

  isSignedIn(): Observable {
    // Implementation

The goal is to stub the isSignedIn() method in your Cypress tests. However, directly importing and stubbing this service in Cypress can lead to issues because Cypress operates outside the browser’s scope.

Solution: Accessing Angular Services within Cypress

To stub the isSignedIn() method, you need to access the instance of AuthenticationService within Angular’s scope. Follow these steps:

Step 1: Expose the Service to the Browser’s Window Object

Modify your Angular component to expose the authentication service:

    export class AppComponent {
  constructor(private authenticationService: AuthenticationService) {
    window['authenticationService'] = authenticationService;

Step 2: Use Cypress to Stub the Service Method

In your Cypress test, use the cy.window() function to access the browser’s window object and then stub the isSignedIn() method:

    import { BehaviorSubject } from 'rxjs';

context('albums', () => {
  it('get albums', () => {
    cy.window().then((window) => {
      const serviceFromAngularScope = window['authenticationService'];
      cy.stub(serviceFromAngularScope, 'isSignedIn').returns(new BehaviorSubject(true));

Alternative Approaches

Another approach is to manipulate session storage or cookies to bypass the authentication flow. This can be done by setting session storage items directly in Cypress:

    cy.window().then(window => {
  window.sessionStorage.setItem('key', 'value');


Stubbing out Angular services in Cypress requires a bit of setup, but with the right approach, you can effectively mock your authentication service and run your end-to-end tests seamlessly. For more detailed guides on testing, check out our blog on checking text presence using Selenium or managing multiple tabs in Selenium.

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