尝试在测试规范中构建表单时出错。表单构建功能还可以构建子表单数组。寻找测试的最佳方法

component.ts

buildForm() {
    return this.peopleForm = this.fb.group({
      people: this.fb.array([this.buildSubFormGroup()]),effective_date: [this.firstOfNextMonth(),Validators.required]
    });
  }

buildSubFormGroup(type: string = 'primary') {
    return this.fb.group({
      type: [type],first_name: ['',Validators.required],last_name: ['',dob: ['',gender: ['',uses_tobacco: ['',affordable_care: ['',is_pregnant: [''],});
  }

component.spec.ts

it('should be able to build the peopleForm',() => {
    component.buildForm();
    fixture.detectChanges();
    expect(component.peopleForm.controls['type'].value).not.toBeNull();
  });

错误： 错误：没有附加到名称为“有效日期”的表单控件元素的FormControl实例