Skip to main content

Angular 5 and 4 Unit Test - Karma and Jasmine!

Introduction to Angular Test- Driven Development | Unit/e2e Testing Guides‎
ü  What is Unit Test in Angular?
ü  What Is Integration Testing in Angular?
ü  How to Test a components inputs as well as its outputs?
ü  How to Interact with a components view?

Types of Test in Angular 4/2 and Angular
The all great developer knows his/her testing tools uses. Understanding your tools for testing is essential before diving into writing tests.

The Testing is depends on your project requirements and the project cost. The types of Testing looks like -
1.     Unit Test
2.     Integration Test
3.     End to End (e2e) Test

Unit TestWhat is Unit Test in Angular? The Unit Test is used to testing a single function, single components in Isolation. This is very fast.

In this Test, we are not able to say that everything is all right in the application. Just for a single Unit or function assure that working fine.

Integration Testing – What Is Integration Testing in Angular? The Integration Testing is used to testing a component with templates and this testing containing more time as per comparison Unit Test.

End to End Test (e2e) – What is End-to-End Testing in Angular? The End to End Testing is used to testing the entire application looks like -
1.     All User Interactions
2.     All Service Calls
3.     Authentication/Authorization of app
4.     Everything of App

This is the actual testing of your append it is fast action.
Unit testing and Integrations testing will do as fake calls but e2e testing is done with your actual Services and APIs calls.

Recommended Unit Testing Tools – Angular 4/2 and Angular
·       Karma
·       Jasmine and
·       QUnit

Test Function – After installing everything as per your project requirements, CREATE your project.
The following Steps –
ü  ng new YourTestProject
ü  ng install
ü  ng serve/ng test

Note – If you are going to development then type ng server command and if you want to test your project, you should type ng test command.  After type ng test command and press inter. It’s taking some time to installing everything in your project for test.

Test functions
1.     describe – Test suit (just a function)
2.     it  - The spec or test
3.     expect -  Expected outcome.

Triple Rule of Testing –
1.     Arrange - Create and Initialize the Components
2.     Act -  Invoke the Methods/Functions of Components
3.     Assert - Assert the expected outcome/behaviour

Best Practices - The quick list of best practices.
ü  Use beforeEach() to Initialize the context for your tests.
ü  Make sure the string descriptions you put in describe () and it () make sense as output
ü  Use after () and afterEach () to clean-up your tests if there is any state that may bleed over.
ü  If any one test is over 15 lines of code, you may need to refactor the test

A Simple Example as –
import { TestBed, async } from '@angular/core/testing';
import { AppComponent } from './app.component';

//describe – Test suit (just a function)
describe('AppComponent', () => {
  beforeEach(async(() => {
      declarations: [AppComponent]

 // it - The spec or test
 it('should have hello property', function() {
  const fixture = TestBed.createComponent(AppComponent);
  const app = fixture.debugElement.componentInstance;

   //expect – This Is For expected outcome.
   expect(app.hello).toBe('Hello, Anil!');

Example 1
app.component.ts –
import { Component } from '@angular/core';

  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
export class AppComponent {
  title = 'app';

app.component.spec.ts –
import { TestBed, async } from '@angular/core/testing';
import { AppComponent } from './app.component';

describe('AppComponent', () => {
  beforeEach(async(() => {
      declarations: [

  it('should create the app', async(() => {
    const fixture = TestBed.createComponent(AppComponent);
    const app = fixture.debugElement.componentInstance;

  it(`should have as title 'app'`, async(() => {
    const fixture = TestBed.createComponent(AppComponent);
    const app = fixture.debugElement.componentInstance;


  it('should render title in a h1 tag', async(() => {
    const fixture = TestBed.createComponent(AppComponent);
    const compiled = fixture.debugElement.nativeElement;

    expect(compiled.querySelector('h1').textContent).toContain('Welcome to app!');

app.component.html –
<div style="text-align:center">
  <h1>  Welcome to {{title}}! </h1>
<h2>Here are some links to help you start: </h2>
    <h2><a target="_blank" rel="noopener" href="">Tour of Examples</a></h2>
    <h2><a target="_blank" rel="noopener" href="">CLI Documentation</a></h2>

Example 2 – Login Testing
import { Component, OnInit, EventEmitter,Input, Output, ViewEncapsulation } from '@angular/core';

  selector: 'app-login',
  templateUrl: './login.component.html',
  styleUrls: ['./login.component.css'],
  encapsulation: ViewEncapsulation.None
export class LoginComponent implements OnInit {

  @Output() loggedIn = new EventEmitter<User>();
  @Input() enabled = true;

  constructor() { }

  ngOnInit() {  }

  login(email, password) {
    if (email && password) {
       this.loggedIn.emit(new User(email, password));
    console.log(`Login ${email} ${password}`);

export class User {
  constructor(public email: string, public password: string) {

login.component.spec.ts –
import { async, ComponentFixture, TestBed } from '@angular/core/testing';
import {Component, DebugElement} from "@angular/core";
import {LoginComponent, User } from './login.component';
import {By} from "@angular/platform-browser";

describe('LoginComponent', () => {
  let component: LoginComponent;
  let fixture: ComponentFixture<LoginComponent>;
  let submitElement: DebugElement;
  let loginElement: DebugElement;
  let passwordElement: DebugElement;

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

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

    submitElement = fixture.debugElement.query(By.css('button'));
    loginElement = fixture.debugElement.query(By.css('input[type=email]'));
    passwordElement = fixture.debugElement.query(By.css('input[type=password]'));

  it('Setting enabled to false disabled the submit button', () => {
    component.enabled = false;

    //Expected outcome

  it('Setting enabled to true enables the submit button', () => {
    component.enabled = true;

    //Expected outcome

  it('Entering email and password emits loggedIn event', () => {
    let user: User;

    loginElement.nativeElement.value = "";
    passwordElement.nativeElement.value = "$ystem!1356";

    // Subscribe to the Observable and store the user in a local variable.
    component.loggedIn.subscribe((value) => user = value);

    // This sync emits the event and the subscribe callback gets executed above
    submitElement.triggerEventHandler('click', null);

    //Expected outcome


login.component.html –
  <input type="email" #email>
  <input type="password" #password>
  <button type="button"
          (click)="login(email.value, password.value)"

I hope you are enjoying with this post! Please share with you friends!! Thank you!!!
By Anil Singh | Rating of this article (*****)

Popular posts from this blog

39 Best Object Oriented JavaScript Interview Questions and Answers

Most Popular 37 Key Questions for JavaScript Interviews. What is Object in JavaScript? What is the Prototype object in JavaScript and how it is used? What is "this"? What is its value? Explain why "self" is needed instead of "this". What is a Closure and why are they so useful to us? Explain how to write class methods vs. instance methods. Can you explain the difference between == and ===? Can you explain the difference between call and apply? Explain why Asynchronous code is important in JavaScript? Can you please tell me a story about JavaScript performance problems? Tell me your JavaScript Naming Convention? How do you define a class and its constructor? What is Hoisted in JavaScript? What is function overloadin

List of Countries, Nationalities and their Code In Excel File

Download JSON file for this List - Click on JSON file    Countries List, Nationalities and Code Excel ID Country Country Code Nationality Person 1 UNITED KINGDOM GB British a Briton 2 ARGENTINA AR Argentinian an Argentinian 3 AUSTRALIA AU Australian an Australian 4 BAHAMAS BS Bahamian a Bahamian 5 BELGIUM BE Belgian a Belgian 6 BRAZIL BR Brazilian a Brazilian 7 CANADA CA Canadian a Canadian 8 CHINA CN Chinese a Chinese 9 COLOMBIA CO Colombian a Colombian 10 CUBA CU Cuban a Cuban 11 DOMINICAN REPUBLIC DO Dominican a Dominican 12 ECUADOR EC Ecuadorean an Ecuadorean 13 EL SALVADOR

25 Best Vue.js 2 Interview Questions and Answers

What Is Vue.js? The Vue.js is a progressive JavaScript framework and used to building the interactive user interfaces and also it’s focused on the view layer only (front end). The Vue.js is easy to integrate with other libraries and others existing projects. Vue.js is very popular for Single Page Applications developments. The Vue.js is lighter, smaller in size and so faster. It also supports the MVVM ( Model-View-ViewModel ) pattern. The Vue.js is supporting to multiple Components and libraries like - ü   Tables and data grids ü   Notifications ü   Loader ü   Calendar ü   Display time, date and age ü   Progress Bar ü   Tooltip ü   Overlay ü   Icons ü   Menu ü   Charts ü   Map ü   Pdf viewer ü   And so on The Vue.js was developed by “ Evan You ”, an Ex Google software engineer. The latest version is Vue.js 2. The Vue.js 2 is very similar to Angular because Evan You was inspired by Angular and the Vue.js 2 components looks like -

React | Encryption and Decryption Data/Text using CryptoJs

To encrypt and decrypt data, simply use encrypt () and decrypt () function from an instance of crypto-js. Node.js (Install) Requirements: 1.       Node.js 2.       npm (Node.js package manager) 3.       npm install crypto-js npm   install   crypto - js Usage - Step 1 - Import var   CryptoJS  =  require ( "crypto-js" ); Step 2 - Encrypt    // Encrypt    var   ciphertext  =  CryptoJS . AES . encrypt ( JSON . stringify ( data ),  'my-secret-key@123' ). toString (); Step 3 -Decrypt    // Decrypt    var   bytes  =  CryptoJS . AES . decrypt ( ciphertext ,  'my-secret-key@123' );    var   decryptedData  =  JSON . parse ( bytes . toString ( CryptoJS . enc . Utf8 )); As an Example,   import   React   from   'react' ; import   './App.css' ; //Including all libraries, for access to extra methods. var   CryptoJS  =  require ( "crypto-js" ); function   App () {    var   data

.NET Core MVC Interview Questions and Answers

» OOPs Interview Questions Object Oriented Programming (OOP) is a technique to think a real-world in terms of objects. This is essentially a design philosophy that uses a different set of programming languages such as C#... Posted In .NET » .Net Constructor Interview Questions A class constructor is a special member function of a class that is executed whenever we create new objects of that class. When a class or struct is created, its constructor is called. A constructor has exactly the same name as that of class and it does not have any return type… Posted In .NET » .NET Delegates Interview Questions Delegates are used to define callback methods and implement event handling, and they are declared using the "delegate" keyword. A delegate in C# is similar to function pointers of C++, but C# delegates are type safe… Posted In .NET » ASP.Net C# Interview Questions C# was developed by Microsoft and is used in essentially all of their products. It is mainly used for