订阅的单元测试

Question

我有一个对ngOninit进行get调用的组件

ngOnInit(): void {
    this.setMemberRoles();
  }

  public setMemberRoles(): void {
    this.teamService.getMemberRoles().subscribe((response: ICreatedByRole) => {
      this.memberRoles = response;
    });
  }

我想为此编写测试用例：

it('should set member roles in variable member roles', async(() => {
    let response: ICreatedByRole[] = [];

    spyOn(teamServiceStub, 'getMemberRoles').and.returnValue(of(response));
    component.setMemberRoles();
    fixture.detectChanges();
    expect(component.memberRoles).toEqual(response);
  }));

我已经尝试过，但是会引发错误

 <spyOn> : could not find an object to spy upon for getMemberRoles()
    Usage: spyOn(<object>, <methodName>)

有什么主意吗？

Answer 1

模拟teamService。

class MockTeamService {

 getMemberRoles {
  return 'fake response'
   }
}

将此MockTeamService注入提供商中。

{provider: TeamService, useClass: MockTeamService}

获取注入的服务。

teamService = TestBed.get(TeamService);

然后监听：

const memberSpy = spyOn(teamService, 
'getMemberRoles').and.returnValue(of(response));