Skip to main content

Isolated Unit Tests vs. Angular Testing Utilities - [Angular 4 and Angular 2]

What Are Isolated Unit Tests?
The Isolated unit tests check-up an instance of a class itself without using any Angular dependence or any injected values.

Mostly application tester creates a test instance of the class with new keyword and supplying test doubles for the constructor parameters and then investigation the test instance.

The isolated unit tests don't realize how components interact with Angular and also don't realize how a component class interacts with its own template or components.

For testing Angular Pipes and Services - we should write isolated unit tests!

The isolated unit tests don't realize how components interact with Angular and also don't realize how a component class interacts with its own template or components.

Stayed Informed - Angular 4 Docs with Examples

The most familiar Unit Test for the Tester and Developers as following -
1.     Create an Instances directly with new keyword
2.     Angular Agnostic Testing Techniques
3.     Exhibit Standard
4.     Substitute Test

The Most of the Tester and Developers are tried to avoid Unit Testing following methodology-
1.     Import from the Angular Test Libraries - @angular/core/testing
2.     Configure Angular module
3.     Prepare Dependency Injection Providers
4.     Call Inject or (async/fakeAsync)

Example as – This example is used to display Credit Card Number with a custom formatted in the user templates. 
import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
    name: 'barcode',
    pure: false
})
export class BarCodePipe implements PipeTransform {
    transform(value: string, args: any[]): string {
        if (!value) {
            return '';
        }
        return "****-****_" + (value.length > 8 ? (value.length - 8): '')
    }
}

Unit Testing to the Pipe - BarCodePipe
describe('BarCodePipe', () => {
  let pipe = new BarCodePipe();
 
  //Todo tests ...
});

What Are Angular Testing Utilities?

The Angular Testing utilities include the TestBed class and helper functions from the test libraries - @angular/core/testing.

Stayed Informed - Angular 2 Docs with Examples

The TestBed class is one of the principal Angular testing utilities!

The TestBed class is responsible for configuring and initializing the environment that we are going to write our tests in by calling TestBed.configureTestingModule.

The TestBed.configureTestingModule is used to define the environment that we want our component under test to live in.

The Angular testing utility APIs are –
1.     getTestBed
2.     async
3.     fakeAsync
4.     tick
5.     inject
6.     discardPeriodicTasks
7.     flushMicrotasks
8.     ComponentFixtureAutoDetect     

The most important static methods are –
1.     configureTestingModule
2.     compileComponents
3.     createComponent
4.     overrideModule
5.     overrideComponent
6.     overrideDirective
7.     overridePipe
8.     get
9.     initTestEnvironment
10.  resetTestEnvironment

Example As –

beforeEach(() => {
  fixture = TestBed.configureTestingModule({
    declarations: [YourComponent ]
  })
  .createComponent(YourComponent);
});

References -


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

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 -

nullinjectorerror no provider for httpclient angular 17

In Angular 17 where the standalone true option is set by default, the app.config.ts file is generated in src/app/ and provideHttpClient(). We can be added to the list of providers in app.config.ts Step 1:   To provide HttpClient in a standalone app we could do this in the app.config.ts file, app.config.ts: import { ApplicationConfig } from '@angular/core'; import { provideRouter } from '@angular/router'; import { routes } from './app.routes'; import { provideClientHydration } from '@angular/platform-browser'; //This (provideHttpClient) will help us to resolve the issue  import {provideHttpClient} from '@angular/common/http'; export const appConfig: ApplicationConfig = {   providers: [ provideRouter(routes),  provideClientHydration(), provideHttpClient ()      ] }; The appConfig const is used in the main.ts file, see the code, main.ts : import { bootstrapApplication } from '@angular/platform-browser'; import { appConfig } from '

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

Angular 2, 4, 5, 6, 7, 8 and 9 Interview Questions and Answers -Books

» Are you preparing for Angular Interview? Buy this book (Including Angular 8, 7, 6, 5,4, 2) Interview Q/A Interview Q/A Interview Q/A Interview Q/A Interview Q/A Interview Q/A Interview Q/A » A Complete Guide Book of Angular 9 This is a concise, complete overview of the key aspects of Angular 9. It is fully up to date with the latest release of Angular. This article provide all the important aspects required for angular developers looking for brief and useful content... Posted In Angular 9 » A Complete Guide Book of Angular 8 This is a concise, complete overview of the key aspects of Angular 9. It is fully up to date with the latest release of Angular. This article provide all the important aspects required for angular developers looking for brief and useful content... Posted In Angular 8 » A Complete Guide Book of Angular 7 This is a concise, complete overview of the key aspects of Angular 7. It is fully up to date with the latest release of Angular. This