Angular TypeError:无法设置属性'；formGroup'；未定义的

我有一些像这样的组件

import { Component, Input } from '@angular/core';
import { WorkingHours } from '../../../../../hours';
import { FormGroup } from '@angular/forms';

@Component({
  selector: '[app-working-hours]',
  templateUrl: './working-hours.component.html',
  styleUrls: ['./working-hours.component.scss']
})

export class WorkingHoursComponent {
  @Input() properties: { formGroup: FormGroup; workingHours: WorkingHours; index: number; period: string; };
  get formControls(): any { return this.properties.formGroup.controls; }

  constructor() {
  }
}

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

import { WorkingHoursComponent } from './working-hours.component';
import { ReactiveFormsModule, FormControl, FormGroup } from '@angular/forms';

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

    beforeEach(async(() => {
        imports.push(ReactiveFormsModule);

        TestBed.configureTestingModule({
            imports: imports,
            declarations: [
                WorkingHoursComponent
            ],
            schemas: [NO_ERRORS_SCHEMA]
        })
            .compileComponents();
    }));

    beforeEach(() => {
        fixture = TestBed.createComponent(WorkingHoursComponent);
        component = fixture.componentInstance;
        let fixed = new FormControl(false);
        let startTime = new FormControl('');
        let endTime = new FormControl('');
        component.properties.formGroup = new FormGroup({
          fixed,
          startTime,
          endTime
        });
        fixture.detectChanges();
    });

    it('should create', () => {
        expect(component).toBeTruthy();
    });
});

然后像这样测试

import { Component, Input } from '@angular/core';
import { WorkingHours } from '../../../../../hours';
import { FormGroup } from '@angular/forms';

@Component({
  selector: '[app-working-hours]',
  templateUrl: './working-hours.component.html',
  styleUrls: ['./working-hours.component.scss']
})

export class WorkingHoursComponent {
  @Input() properties: { formGroup: FormGroup; workingHours: WorkingHours; index: number; period: string; };
  get formControls(): any { return this.properties.formGroup.controls; }

  constructor() {
  }
}

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

import { WorkingHoursComponent } from './working-hours.component';
import { ReactiveFormsModule, FormControl, FormGroup } from '@angular/forms';

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

    beforeEach(async(() => {
        imports.push(ReactiveFormsModule);

        TestBed.configureTestingModule({
            imports: imports,
            declarations: [
                WorkingHoursComponent
            ],
            schemas: [NO_ERRORS_SCHEMA]
        })
            .compileComponents();
    }));

    beforeEach(() => {
        fixture = TestBed.createComponent(WorkingHoursComponent);
        component = fixture.componentInstance;
        let fixed = new FormControl(false);
        let startTime = new FormControl('');
        let endTime = new FormControl('');
        component.properties.formGroup = new FormGroup({
          fixed,
          startTime,
          endTime
        });
        fixture.detectChanges();
    });

    it('should create', () => {
        expect(component).toBeTruthy();
    });
});

从'@angular/core/testing'导入{async，ComponentFixture，TestBed}；
从'@angular/core'导入{NO_ERRORS_SCHEMA}；
从“./working hours.component”导入{working hours component}；
从'@angular/forms'导入{ReactiveFormsModule，FormControl，FormGroup}；
描述（'WorkingHoursComponent'，（）=>{
let组件：工作时间组件；
let夹具：组件夹具；
beforeach（异步（（）=>{
imports.push（ReactiveFormsModule）；
TestBed.configureTestingModule({
进口:进口,，
声明：[
工作时间组件
],
架构：[无错误\u架构]
})
.compileComponents（）；
}));
在每个之前（（）=>{
fixture=TestBed.createComponent（工作时间组件）；
组件=fixture.componentInstance；
let fixed=新表单控件（false）；
让startTime=newformcontrol（“”）；
让endTime=新表单控件（“”）；
component.properties.formGroup=新的formGroup({
固定的，
开始的时候，
结束时间
});
fixture.detectChanges（）；
});
它（'应该创建'，（）=>{
expect（component.toBeTruthy（）；
});
});

但我总是犯错误 TypeError:无法设置未定义的属性“formGroup”

---

有人能告诉我哪里错了吗，谢谢？

因为属性没有默认值，请尝试此操作

component.properties.formGroup={
formGroup:新formGroup({
固定的，
开始的时候，
结束时间
}),
索引：0，
句号：“句号”
}