Testing - Part 2 Building The Testing App

Overview

Time: 5min

In this module, we will add the code to make the Chuck Norris Jokes Application

Learning Outcomes

• How to make a simple application to test
• Adding a basic module with a component and a service

Add a Joke Component

Time: 15min

• Make a new joke component with the Angular CLI with:-
• Inline Template '--it'
• Inline Styles '--is'
• No test file '--spec false'

ng g c joke --it --is --spec false

• Confirm the reference to joke component exists in the main app.module.ts file and add it if it does not exist

src/app/app.module.ts

@NgModule({
  declarations: [
    AppComponent,
    JokeComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})

Add Bootstrap for styling

Time: 10min

• Add bootstrap with npm to the project

npm i bootstrap --save

• Add a reference to the bootstrap.css file in the node_modules folder in the angular-cli.json files styles[0] section. This will tell the CLI to inline this CSS file in the index.html file at build time.

"styles": [
    "styles.css",
    "../node_modules/bootstrap/dist/css/bootstrap.min.css"
]

Add Joke Component Logic

Time: 10min

• Add a getJoke() function to the component class
• Add a title property and set it to "Chuck Norris Jokes"
• Add a joke property of type string
• Add the joke component selectors onto the app.components HTML template inside a div with a bootstrap container CSS class

src/app/app.component.html

<div class="container">
  <app-joke></app-joke>
</div>

src/app/joke/joke.component.ts

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

@Component({
  selector: 'app-joke',
  template: `
    <h1>{{title}}</h1>
    <div class="well">
      <p>{{joke}}</p>
      <button class="btn btn-success" (click)="getJoke()">Get next     joke</button>
    </div>
  `,
})
export class JokeComponent implements OnInit {
  joke: string;
  title = 'Chuck Norris Jokes';

  constructor() { }

  ngOnInit() {
    this.getJoke();
  }

  getJoke() {
    this.joke = 'funny joke text';
  }

}

• Add a binding for the joke property to the component template
• Add a button with a click handler to call getJoke() on the component
• Add a binding in a h1 element for the component title property

src/app/joke/joke.component.ts

  template: `
    <h1>{{title}}</h1>
    <div class="well">
      <p>{{joke}}</p>
      <button class="btn btn-success" (click)="getJoke()">Get next     joke</button>
    </div>
  `,

Add a Joke Service

Time: 10min

• Make a new joke service with the Angular CLI

ng g service joke/joke

• Add a getJoke() function to the component service
• Add the import statements for Observable, Http and rxjs/add/operator/map

This is a simple service, and hence we will not add error handling which we would normally do. You can see we are using an open source Chuck Norris Jokes API, you can try it out by pasting this link into the URL of any browser http://api.icndb.com/jokes/random

src/app/joke/joke.service.ts

import { Injectable } from '@angular/core';
import { Http } from '@angular/http';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/map';

@Injectable()
export class JokeService {

  constructor(private http: Http) { }

  getJoke(): Observable<any> {
    return this.http.get(`http://api.icndb.com/jokes/random`)
      .map(response => response.json().value.joke);
  }

}

• Register the joke service with the chucknorris module.

src/app/app.module.ts

@NgModule({
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { HttpModule } from '@angular/http';

import { AppComponent } from './app.component';
import { JokeComponent } from './joke/joke.component';
import { JokeService } from './joke/joke.service';

@NgModule({
  declarations: [
    AppComponent,
    JokeComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule
  ],
  providers: [JokeService],
  bootstrap: [AppComponent]
})
export class AppModule { }

Inject and call the Joke Service from the Joke Component

Time: 5min

• Inject the joke service
• Swap out the hard coded return value in the getJoke() function with a call to the joke services getJoke() function

src/app/joke/joke.component.ts

import { Component, OnInit } from '@angular/core';
import { JokeService } from './joke.service';

@Component({
  selector: 'app-joke',
  template: `
    <h1>{{title}}</h1>
    <div class="well">
      <p>{{joke}}</p>
      <button class="btn btn-success" (click)="getJoke()">Get next     joke</button>
    </div>
  `,
})
export class JokeComponent implements OnInit {
  joke: string;
  title = 'Chuck Norris Jokes';

  constructor(private jokeService: JokeService) { }

  ngOnInit() {
    this.getJoke();
  }

  getJoke() {
    this.jokeService.getJoke()
      .subscribe(joke => this.joke = joke);
  }

}

Start the Angular CLI server and inspect the app

Time: 2min

• Start the server

ng serve