如何在订阅 Angular7 单元测试用例中对代码进行单元测试

Question

我想要进行单元测试并获得所有代码的覆盖率，但我无法获得订阅内存在的代码的覆盖率我能够监视服务和功能，但在订阅内我无法进行单元测试并获得代码覆盖率。以下是 Angular 7 代码。

LoadListData(type) {
    this.itemListEnvName = [];
    if (type === 'EnvirnmentList') {
      this.environmentBookingService.getBookedEnv()
        .subscribe(
          (environmentBookingsData: EbEnvironmentBooking[]) => {
            if (environmentBookingsData.length > 0) {
              this.itemListEnvNameList = environmentBookingsData;
              this.itemListEnvName = [];
              this.itemListEnvNameList.forEach(element => {
                const obj = {};
                obj['id'] = element['environmentId'];
                obj['itemName'] = element['environmentName'];
                this.itemListEnvName.push(obj);
                this.generateCheckDisable = false;
              });
            } else {
              this.generateCheckDisable = true;
            }
          },
          (error) => {
            this.showMessage('No Response From Delivery DB API');
          }
        );
    } else {

      this.showMessage('No Response From Delivery DB API');
    }


  }

单元测试用例内的代码就像

 it('should call getBookedEnv service ', function () {
    const service = TestBed.get(EnvironmentBookingService); // get your service
    spyOn(service, 'getBookedEnv').and.callThrough(); // create spy
    component.LoadListData('EnvirnmentList');
    expect(service.getBookedEnv).toHaveBeenCalledWith();

  });

如何在 subscribe ie 中对代码进行单元测试

if (environmentBookingsData.length > 0) {
              this.itemListEnvNameList = environmentBookingsData;
              this.itemListEnvName = [];
              this.itemListEnvNameList.forEach(element => {
                const obj = {};
                obj['id'] = element['environmentId'];
                obj['itemName'] = element['environmentName'];
                this.itemListEnvName.push(obj);
                this.generateCheckDisable = false;
              });
            } else {
              this.generateCheckDisable = true;
            }

Answer 1

如果您想测试里面的代码subscribe，您必须模拟您的服务调用，然后测试您在里面修改的组件变量subscribe，例如this.itemListEnvName和this.generateCheckDisable。

这可能看起来像这样：

 it('should call getBookedEnv service ', function () {
    const service = TestBed.get(EnvironmentBookingService); // get your service
    spyOn(service, 'getBookedEnv').and.callFake(() => {
      return of([]); // or return a list of bookings in case you want to test the first part of the if statement 
    });
    component.LoadListData('EnvironmentList');
    expect(service.getBookedEnv).toHaveBeenCalledWith();

    // additional tests that verify the inside of the subscribe (change below in case the mocked service returned something)
    expect(component.itemListEnvName).equalTo([]);
    expect(component.generateCheckDisable).equalTo(false);
  });