TestBed와 컴포넌트 픽스처

TestBed가 존재하는 이유

configureTestingModule

import { TestBed } from '@angular/core/testing';
import { CounterComponent } from './counter.component';

beforeEach(() => {
  TestBed.configureTestingModule({
    imports: [CounterComponent],
  });
});

ComponentFixture 만들기

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

let fixture: ComponentFixture<CounterComponent>;

beforeEach(() => {
  fixture = TestBed.createComponent(CounterComponent);
});

컴포넌트 인스턴스에 접근하기

it('creates the component', () => {
  const fixture = TestBed.createComponent(CounterComponent);
  const component = fixture.componentInstance;
  expect(component).toBeTruthy();
  expect(component.count).toBe(0);
});

detectChanges가 렌더링을 실행합니다

it('renders initial value', () => {
  const fixture = TestBed.createComponent(CounterComponent);
  fixture.detectChanges(); // now bindings are applied
  const el = fixture.nativeElement as HTMLElement;
  expect(el.textContent).toContain('0');
});

nativeElement와 debugElement

const native = fixture.nativeElement;       // HTMLElement
const debug = fixture.debugElement;         // DebugElement
console.log(debug.componentInstance === fixture.componentInstance); // true

테스트 모듈의 Provider

TestBed.configureTestingModule({
  imports: [CounterComponent],
  providers: [
    { provide: LoggerService, useValue: { log: () => {} } },
  ],
});

외부 템플릿을 위한 compileComponents

beforeEach(async () => {
  await TestBed.configureTestingModule({
    imports: [ProfileComponent],
  }).compileComponents();
});

완전한 최소 테스트

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

  beforeEach(() => {
    TestBed.configureTestingModule({ imports: [CounterComponent] });
    fixture = TestBed.createComponent(CounterComponent);
    fixture.detectChanges();
  });

  it('starts at zero', () => {
    expect(fixture.componentInstance.count).toBe(0);
  });
});

서비스를 위한 TestBed.inject

const logger = TestBed.inject(LoggerService);
expect(logger).toBeDefined();

테스트 사이에 초기화하기

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