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テスト

パイプのテスト

Angularのテストユーティリティを使わずにパイプをテストできます。

TitleCasePipeのテスト

パイプクラスには、入力値を変換された出力値に変換するtransformメソッドが1つあります。 transformの実装は、DOMとほとんどやり取りしません。 ほとんどのパイプは、@Pipeメタデータとインターフェース以外、Angularに依存していません。

各単語の最初の文字を大文字にするTitleCasePipeを考えてみましょう。 正規表現を使った実装を以下に示します。

app/shared/title-case.pipe.ts

      
import {Pipe, PipeTransform} from '@angular/core';@Pipe({name: 'titlecase', standalone: true, pure: true})/** Transform to Title Case: uppercase the first letter of the words in a string. */export class TitleCasePipe implements PipeTransform {  transform(input: string): string {    return input.length === 0      ? ''      : input.replace(/\w\S*/g, (txt) => txt[0].toUpperCase() + txt.slice(1).toLowerCase());  }}

正規表現を使用するものは、徹底的にテストする価値があります。 簡単なJasmineを使用して、期待されるケースとエッジケースを調べます。

app/shared/title-case.pipe.spec.ts

      
import {TitleCasePipe} from './title-case.pipe';describe('TitleCasePipe', () => {  // This pipe is a pure, stateless function so no need for BeforeEach  const pipe = new TitleCasePipe();  it('transforms "abc" to "Abc"', () => {    expect(pipe.transform('abc')).toBe('Abc');  });  it('transforms "abc def" to "Abc Def"', () => {    expect(pipe.transform('abc def')).toBe('Abc Def');  });  // ... more tests ...  it('leaves "Abc Def" unchanged', () => {    expect(pipe.transform('Abc Def')).toBe('Abc Def');  });  it('transforms "abc-def" to "Abc-def"', () => {    expect(pipe.transform('abc-def')).toBe('Abc-def');  });  it('transforms "   abc   def" to "   Abc   Def" (preserves spaces) ', () => {    expect(pipe.transform('   abc   def')).toBe('   Abc   Def');  });});

パイプテストをサポートするDOMテストの作成

これらはパイプの単体テストです。 これらは、TitleCasePipeがアプリケーションコンポーネントに適用されたときに正しく動作しているかどうかを判断できません。

このようなコンポーネントテストを追加することを考えてみましょう。

app/hero/hero-detail.component.spec.ts (pipe test)

      
import {HttpClient, HttpHandler, provideHttpClient} from '@angular/common/http';import {HttpTestingController, provideHttpClientTesting} from '@angular/common/http/testing';import {fakeAsync, TestBed, tick} from '@angular/core/testing';import {provideRouter, Router} from '@angular/router';import {RouterTestingHarness} from '@angular/router/testing';import {asyncData, click} from '../../testing';import {Hero} from '../model/hero';import {sharedImports} from '../shared/shared';import {HeroDetailComponent} from './hero-detail.component';import {HeroDetailService} from './hero-detail.service';import {HeroListComponent} from './hero-list.component';////// Testing Vars //////let component: HeroDetailComponent;let harness: RouterTestingHarness;let page: Page;////// Tests //////describe('HeroDetailComponent', () => {  describe('with HeroModule setup', heroModuleSetup);  describe('when override its provided HeroDetailService', overrideSetup);  describe('with FormsModule setup', formsModuleSetup);  describe('with SharedModule setup', sharedModuleSetup);});///////////////////const testHero = getTestHeroes()[0];function overrideSetup() {  class HeroDetailServiceSpy {    testHero: Hero = {...testHero};    /* emit cloned test hero */    getHero = jasmine      .createSpy('getHero')      .and.callFake(() => asyncData(Object.assign({}, this.testHero)));    /* emit clone of test hero, with changes merged in */    saveHero = jasmine      .createSpy('saveHero')      .and.callFake((hero: Hero) => asyncData(Object.assign(this.testHero, hero)));  }  beforeEach(async () => {    await TestBed.configureTestingModule(      Object.assign({}, appConfig, {        imports: [HeroDetailComponent, HeroListComponent],        providers: [          provideRouter([            {path: 'heroes', component: HeroListComponent},            {path: 'heroes/:id', component: HeroDetailComponent},          ]),          HttpClient,          HttpHandler,          // HeroDetailService at this level is IRRELEVANT!          {provide: HeroDetailService, useValue: {}},        ],      }),    )      .overrideComponent(HeroDetailComponent, {        set: {providers: [{provide: HeroDetailService, useClass: HeroDetailServiceSpy}]},      })      .compileComponents();  });  let hdsSpy: HeroDetailServiceSpy;  beforeEach(async () => {    harness = await RouterTestingHarness.create();    component = await harness.navigateByUrl(`/heroes/${testHero.id}`, HeroDetailComponent);    page = new Page();    // get the component's injected HeroDetailServiceSpy    hdsSpy = harness.routeDebugElement!.injector.get(HeroDetailService) as any;    harness.detectChanges();  });  it('should have called `getHero`', () => {    expect(hdsSpy.getHero.calls.count())      .withContext('getHero called once')      .toBe(1, 'getHero called once');  });  it("should display stub hero's name", () => {    expect(page.nameDisplay.textContent).toBe(hdsSpy.testHero.name);  });  it('should save stub hero change', fakeAsync(() => {    const origName = hdsSpy.testHero.name;    const newName = 'New Name';    page.nameInput.value = newName;    page.nameInput.dispatchEvent(new Event('input')); // tell Angular    expect(component.hero.name).withContext('component hero has new name').toBe(newName);    expect(hdsSpy.testHero.name).withContext('service hero unchanged before save').toBe(origName);    click(page.saveBtn);    expect(hdsSpy.saveHero.calls.count()).withContext('saveHero called once').toBe(1);    tick(); // wait for async save to complete    expect(hdsSpy.testHero.name).withContext('service hero has new name after save').toBe(newName);    expect(TestBed.inject(Router).url).toEqual('/heroes');  }));}////////////////////import {getTestHeroes} from '../model/testing/test-hero.service';const firstHero = getTestHeroes()[0];function heroModuleSetup() {  beforeEach(async () => {    await TestBed.configureTestingModule(      Object.assign({}, appConfig, {        imports: [HeroDetailComponent, HeroListComponent],        providers: [          provideRouter([            {path: 'heroes/:id', component: HeroDetailComponent},            {path: 'heroes', component: HeroListComponent},          ]),          provideHttpClient(),          provideHttpClientTesting(),        ],      }),    ).compileComponents();  });  describe('when navigate to existing hero', () => {    let expectedHero: Hero;    beforeEach(async () => {      expectedHero = firstHero;      await createComponent(expectedHero.id);    });    it("should display that hero's name", () => {      expect(page.nameDisplay.textContent).toBe(expectedHero.name);    });    it('should navigate when click cancel', () => {      click(page.cancelBtn);      expect(TestBed.inject(Router).url).toEqual(`/heroes/${expectedHero.id}`);    });    it('should save when click save but not navigate immediately', () => {      click(page.saveBtn);      expect(TestBed.inject(HttpTestingController).expectOne({method: 'PUT', url: 'api/heroes'}));      expect(TestBed.inject(Router).url).toEqual('/heroes/41');    });    it('should navigate when click save and save resolves', fakeAsync(() => {      click(page.saveBtn);      tick(); // wait for async save to complete      expect(TestBed.inject(Router).url).toEqual('/heroes/41');    }));    it('should convert hero name to Title Case', async () => {      harness.fixture.autoDetectChanges();      // get the name's input and display elements from the DOM      const hostElement: HTMLElement = harness.routeNativeElement!;      const nameInput: HTMLInputElement = hostElement.querySelector('input')!;      const nameDisplay: HTMLElement = hostElement.querySelector('span')!;      // simulate user entering a new name into the input box      nameInput.value = 'quick BROWN  fOx';      // Dispatch a DOM event so that Angular learns of input value change.      nameInput.dispatchEvent(new Event('input'));      // Wait for Angular to update the display binding through the title pipe      await harness.fixture.whenStable();      expect(nameDisplay.textContent).toBe('Quick Brown  Fox');    });  });  describe('when navigate to non-existent hero id', () => {    beforeEach(async () => {      await createComponent(999);    });    it('should try to navigate back to hero list', () => {      expect(TestBed.inject(Router).url).toEqual('/heroes');    });  });}/////////////////////import {FormsModule} from '@angular/forms';import {TitleCasePipe} from '../shared/title-case.pipe';import {appConfig} from '../app.config';function formsModuleSetup() {  beforeEach(async () => {    await TestBed.configureTestingModule(      Object.assign({}, appConfig, {        imports: [FormsModule, HeroDetailComponent, TitleCasePipe],        providers: [          provideHttpClient(),          provideHttpClientTesting(),          provideRouter([{path: 'heroes/:id', component: HeroDetailComponent}]),        ],      }),    ).compileComponents();  });  it("should display 1st hero's name", async () => {    const expectedHero = firstHero;    await createComponent(expectedHero.id).then(() => {      expect(page.nameDisplay.textContent).toBe(expectedHero.name);    });  });}///////////////////////function sharedModuleSetup() {  beforeEach(async () => {    await TestBed.configureTestingModule(      Object.assign({}, appConfig, {        imports: [HeroDetailComponent, sharedImports],        providers: [          provideRouter([{path: 'heroes/:id', component: HeroDetailComponent}]),          provideHttpClient(),          provideHttpClientTesting(),        ],      }),    ).compileComponents();  });  it("should display 1st hero's name", async () => {    const expectedHero = firstHero;    await createComponent(expectedHero.id).then(() => {      expect(page.nameDisplay.textContent).toBe(expectedHero.name);    });  });}/////////// Helpers //////** Create the HeroDetailComponent, initialize it, set test variables  */async function createComponent(id: number) {  harness = await RouterTestingHarness.create();  component = await harness.navigateByUrl(`/heroes/${id}`, HeroDetailComponent);  page = new Page();  const request = TestBed.inject(HttpTestingController).expectOne(`api/heroes/?id=${id}`);  const hero = getTestHeroes().find((h) => h.id === Number(id));  request.flush(hero ? [hero] : []);  harness.detectChanges();}class Page {  // getter properties wait to query the DOM until called.  get buttons() {    return this.queryAll<HTMLButtonElement>('button');  }  get saveBtn() {    return this.buttons[0];  }  get cancelBtn() {    return this.buttons[1];  }  get nameDisplay() {    return this.query<HTMLElement>('span');  }  get nameInput() {    return this.query<HTMLInputElement>('input');  }  //// query helpers ////  private query<T>(selector: string): T {    return harness.routeNativeElement!.querySelector(selector)! as T;  }  private queryAll<T>(selector: string): T[] {    return harness.routeNativeElement!.querySelectorAll(selector) as any as T[];  }}