Unit Testing Angular 9/8 Apps Tutorial with Jasmine & Karma by Example

Unit Testing Angular 9/8 Apps Tutorial with Jasmine & Karma by Example

In this tutorial, we'll quickly learn how to unit test an Angular 9/8 application with Jasmine and Karma.

We'll see how to write unit tests for both the components and services in your Angular application by example.

Unit testing is considered an important phase of software development which is equal in importance to designing and writing the code.

We basically have three types of testing:

  • Unit tests,
  • Integration tests,
  • End to End tests.

Throughout this tutorial, we'll be using unit testing for testing our Angular 9 code.

Angular 9 Unit Testing by Example with Jasmine and Karma

Unit testing consists of writing code for making sure our app code behaves as expected for potential input values.

A unit is a small part of code that achieves a specific task in your code.

In Angular projects generated using Angular CLI, unit tests are based on Jasmine.

According to the official website:

Jasmine is a behavior-driven development framework for testing JavaScript code. It does not depend on any other JavaScript frameworks. It does not require a DOM. And it has a clean, obvious syntax so that you can easily write tests.

Jasmine provides a set of APIs that make writing unit tests easy.

Basically, we have these three methods:

  • it(): A method for initializing a unit test,
  • describe(): A method for creating a suite of tests,
  • expect(): A method for defining expectations.

You don't need to master all the methods of Jasmine and Karma to write unit tests in your Angular 9 application.

What's Karma and Why Using it in Angular?

Along with Jasmine, Karma makes use of a test runner that run tests and provides the details of passed and failed tests.

According to the official:

The main goal for Karma is to bring a productive testing environment to developers. The environment being one where they don't have to set up loads of configurations, but rather a place where developers can just write the code and get instant feedback from their tests. Because getting quick feedback is what makes you productive and creative.

Installing Angular CLI v9

Let's get started by installing Angular CLI 9 to initialize the project we'll be testing.

Head over to a new terminal and run the following command:

npm install -g @angular/cli

Please note that you need to have node and npm installed.

Initializing an Angular 9 Project for Unit Testing

Next, let's initialize our Angular 9 project.

ng new angular-9-unit-tests --style css --routing false

Your Angular 9 project will have Jasmine and Karma installed and configured so you only need to start writing your tests.

Unit Testing Angular Components

Let's now see how to unit test an Angular 9 component by example.

Navigate to your project's folder and generate a new component as follows:

cd angular-9-unit-tests
ng generate component product-list

Open the src/app/product-list/product-list.component.ts file:

import { Component, OnInit } from '@angular/core';

  selector: 'app-product-list',
  templateUrl: './product-list.component.html',
  styleUrls: ['./product-list.component.css']
export class ProductListComponent implements OnInit {

  title = "Product List Component";
  constructor() { }

  ngOnInit() {}

Also a test file that ends with a spec.ts extension is by default added with any new component you generate with Angular CLI. In our case, we have a file called product-list.spec.ts:

import { async, ComponentFixture, TestBed } from '@angular/core/testing';

import { ProductListComponent } from './product-list.component';

describe('ProductListComponent', () => {
  let component: ProductListComponent;
  let fixture: ComponentFixture<ProductListComponent>;

  beforeEach(async(() => {
      declarations: [ ProductListComponent ]

  beforeEach(() => {
    fixture = TestBed.createComponent(ProductListComponent);
    component = fixture.componentInstance;

  it('should create', () => {

Let's now write another test as follows:

it(`should have 'Product List Component' as title`, async(() => {
  fixture = TestBed.createComponent(PizzaComponent);
  component = fixture.debugElement.componentInstance;
  expect(component.title).toEqual('Product List Component');

You can run the test using the ng test command:

ng test

Build an Angular 14 CRUD Example & Tutorial
Angular 9 Components: Input and Output
Angular 13 selectors
Picture-in-Picture with JavaScript and Angular 10
Jasmine Unit Testing for Angular 12
Angular 9 Tutorial By Example: REST CRUD APIs & HTTP GET Requests with HttpClient
Angular 10/9 Elements Tutorial by Example: Building Web Components
Angular 10/9 Router Tutorial: Learn Routing & Navigation by Example
Angular 10/9 Router CanActivate Guards and UrlTree Parsed Routes
Angular 10/9 JWT Authentication Tutorial with Example
Style Angular 10/9 Components with CSS and ngStyle/ngClass Directives
Upload Images In TypeScript/Node & Angular 9/Ionic 5: Working with Imports, Decorators, Async/Await and FormData
Angular 9/Ionic 5 Chat App: Unsubscribe from RxJS Subjects, OnDestroy/OnInit and ChangeDetectorRef
Adding UI Guards, Auto-Scrolling, Auth State, Typing Indicators and File Attachments with FileReader to your Angular 9/Ionic 5 Chat App
Private Chat Rooms in Angular 9/Ionic 5: Working with TypeScript Strings, Arrays, Promises, and RxJS Behavior/Replay Subjects
Building a Chat App with TypeScript/Node.js, Ionic 5/Angular 9 & PubNub/Chatkit
Chat Read Cursors with Angular 9/Ionic 5 Chat App: Working with TypeScript Variables/Methods & Textarea Keydown/Focusin Events
Add JWT REST API Authentication to Your Node.js/TypeScript Backend with TypeORM and SQLite3 Database
Building Chat App Frontend UI with JWT Auth Using Ionic 5/Angular 9
Install Angular 10 CLI with NPM and Create a New Example App with Routing
Styling An Angular 10 Example App with Bootstrap 4 Navbar, Jumbotron, Tables, Forms and Cards
Integrate Bootstrap 4/jQuery with Angular 10 and Styling the UI With Navbar and Table CSS Classes
Angular 10/9 Tutorial and Example: Build your First Angular App
Angular 9/8 ngIf Tutorial & Example
Angular 10 New Features
Create New Angular 9 Workspace and Application: Using Build and Serve
Angular 10 Release Date: Angular 10 Will Focus on Ivy Artifacts and Libraries Support
HTML5 Download Attribute with TypeScript and Angular 9
Angular 9.1+ Local Direction Query API: getLocaleDirection Example
Angular 9.1 displayBlock CLI Component Generator Option by Example
Angular 15 Basics Tutorial by Example
Angular 9/8 ngFor Directive: Render Arrays with ngFor by Example
Responsive Image Breakpoints Example with CDK's BreakpointObserver in Angular 9/8
Angular 9/8 DOM Queries: ViewChild and ViewChildren Example
The Angular 9/8 Router: Route Parameters with Snapshot and ParamMap by Example
Angular 9/8 Nested Routing and Child Routes by Example
Angular 9 Examples: 2 Ways To Display A Component (Selector & Router)
Angular 9/8 Tutorial: Http POST to Node/Express.js Example
Angular 9/8 Feature and Root Modules by Example
Angular 9/8 with PHP: Consuming a RESTful CRUD API with HttpClient and Forms
Angular 9/8 with PHP and MySQL Database: REST CRUD Example & Tutorial
Unit Testing Angular 9/8 Apps Tutorial with Jasmine & Karma by Example
Angular 9 Web Components: Custom Elements & Shadow DOM
Angular 9 Renderer2 with Directives Tutorial by Example
Build Progressive Web Apps (PWA) with Angular 9/8 Tutorial and Example
Angular 9 Internationalization/Localization with ngx-translate Tutorial and Example
Create Angular 9 Calendar with ngx-bootstrap datepicker Example and Tutorial
Multiple File Upload with Angular 9 FormData and PHP by Example
Angular 9/8 Reactive Forms with Validation Tutorial by Example
Angular 9/8 Template Forms Tutorial: Example Authentication Form (ngModel/ngForm/ngSubmit)
Angular 9/8 JAMStack By Example
Angular HttpClient v9/8 — Building a Service for Sending API Calls and Fetching Data
Styling An Angular 9/8/7 Example App with Bootstrap 4 Navbar, Jumbotron, Tables, Forms and Cards

✋If you have any questions about this article, ask them in our GitHub Discussions 👈 community. You can also Gitter

✋ Want to master Angular 14? Read our angular tutorial and join our #DailyAngularChallenge where we learn to build components, directives, services, pipes and complete web, mobile, and desktop applications with latest Angular version.

✋ Make sure to join our Angular 14 Dev Community 👈 to discuss anything related to Angular development.

❤️ Like our page and subscribe to our feed for updates!

Find a list of emojis to copy and paste