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Table of contents
1.
Introduction
2.
Angular Testing Library
3.
Examples
4.
Frequently Asked Questions
5.
Conclusion
Last Updated: Mar 27, 2024
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Angular Testing Library

Author Parth Jain
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Basics of Javascript
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Introduction

This blog will help you understand the Angular Testing Library with an example.
Angular Testing Library is essentially a testing library that builds on top of the DOM Testing Library by adding APIs for working with Angular components.

Angular Testing Library

The Angular Testing Library is a light and efficient solution for testing an Angular component. Angular Testing Library provides utility functions on top of the DOM(Document Object Model) Testing Library in a way that enables better testing practices, and its primary guiding principle is
The more a test resembles the way software is used, the more effortless it is to understand and provides more confidence.
Hence, instead of dealing with instances of a rendered Angular component, the tests will work with the actual DOM nodes.
Essentially, a developer has the ability to query the DOM similar to how a user does with the help of Utilities in the Angular Testing Library. Meaning being able to find links and buttons from a text.
Lastly, the Angular Testing Library promotes a more accessible and friendly application by allowing a developer to test a component the way an end-user would.
The Angular Testing Library:

  • Is testing framework that runs on every test framework
  • Re-exports the query and fireEvent utility functions from the DOM Testing Library.
  • Envelopes fireEvent functions of a component in order to call detectChanges() after event occurs automatically.
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Examples

counter.component.ts

@Component({
 selector: 'counter',
 template: `
   <button (click)="dec()">-</button>
   <span data-testid="count">Current Count: {{ counter }}</span>
   <button (click)="inc()">+</button>
 `,
})
export class CounterComponent {
 @Input() counter = 10

 inc() {
   this.counter += 1
 }

 dec() {
   this.counter -= 1
 }
}

counter.component.spec.ts

import {render, screen, fireEvent} from '@testing-library/angular'
import {CounterComponent} from './counter.component.ts'

describe('Counter', () => {
 test('will render the counter', async () => {
   await render(CounterComponent, {
     componentProperties: {counter: 5},
   })

   expect(screen.getByText('Current Count: 5')).toBeInTheDocument()
 })


 test('will increment the counter upon click', async () => {
   await render(CounterComponent, {
     componentProperties: {counter: 5},
   })

   fireEvent.click(screen.getByText('+'))

   expect(screen.getByText('Current Count: 6')).toBeInTheDocument()
 })
})

Frequently Asked Questions

  1. What is the Angular testing library?
    The Angular Testing Library is a light and efficient solution to test an Angular component. Furthermore, the Angular testing library provides various utility functions on top of the DOM Testing Library in a way that promotes better testing practices.
  2. What is a testing library?
    The Testing Library is a family of libraries that is a very lightweight solution for testing without all the implementation details. The principal utilities it provides involve querying for nodes similarly to how users would find them. In this way, the testing library helps ensure your tests give you confidence in your UI code.
  3. How to use the Angular testing library in a project?
    To install the Angular testing library in a project, simply type the following code.
    npm install --save-dev @testing-library/angular
  4. Can unit tests be written with the Angular Testing library?
    Yes, It is indeed possible to write unit and integration tests with the Angular Testing library. 
  5. What is the best Angular testing framework?
    Karma
    Jasmine
    Mocha
    Jest
    Selenium Webdriver
    These are some of the best Angular Testing frameworks.

Conclusion

In this article, we have extensively discussed the Angular Testing Library. If you are Preparing for interview and don't know where to start, we have got you covered, check out our expert curated courses on our website, You can also check out Coding Ninjas Studio to practice frequently asked interview problems. We hope that this blog has helped you enhance your knowledge regarding Angular and if you would like to learn more, check out our articles.Do upvote our blog to help other ninjas grow. Happy Coding!"

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