如何使用 overrideModule / overrideProvider 等方法

demo.component.spec.ts

import { async, ComponentFixture, TestBed } from '@angular/core/testing';
import { RouterTestingModule } from '@angular/router/testing';
import { ActivatedRoute } from '@angular/router';
import { DemoComponent } from './demo.component';
import { of } from 'rxjs/observable/of';
import { NgModule } from '@angular/core';

@NgModule({
  declarations: [DemoComponent],
  providers: [
    {
      provide: ActivatedRoute,
      useValue: {
        data: of({ actionType: 'abc' })
      }
    }
  ]
})
class SomeModule {}

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

  beforeEach(async(() => {
    TestBed.configureTestingModule({ imports: [SomeModule] });
  }));

  describe('使用原本的 module', () => {
    beforeEach(() => {
      fixture = TestBed.createComponent(DemoComponent);
      component = fixture.componentInstance;
      fixture.detectChanges();
    });

    it('actionType should equal abc', async(() => {
      expect(component.actionType).toBe('abc');
    }));
  });

  describe('使用修正後的 module', () => {
    beforeEach(() => {
      TestBed.overrideModule(SomeModule, {
        set: {
          providers: [
            {
              provide: ActivatedRoute,
              useValue: {
                data: of({ actionType: '123' })
              }
            }
          ]
        }
      });
    });

    beforeEach(() => {
      fixture = TestBed.createComponent(DemoComponent);
      component = fixture.componentInstance;
      fixture.detectChanges();
    });

    it('actionType should equal 123', async(() => {
      expect(component.actionType).toBe('123');
    }));
  });

  describe('使用修正後的 provider', () => {
    beforeEach(() => {
      TestBed.overrideProvider(ActivatedRoute, {
        useValue: {
          data: of({ actionType: 'def' })
        }
      });
    });

    beforeEach(() => {
      fixture = TestBed.createComponent(DemoComponent);
      component = fixture.componentInstance;
      fixture.detectChanges();
    });

    it('actionType should equal def', async(() => {
      expect(component.actionType).toBe('def');
    }));
  });
});