类型错误：无法读取未定义的属性“id” - Angular 8 测试

Question

尝试在我的 angular 8 应用程序中执行单元测试时，我收到 TypeError: cannot read property 'id' of undefined 。

这是我的模板

<h4>{{student.id}}</h4>

这是我的组件

import {Component, EventEmitter, Input, OnInit} from '@angular/core';

import { Student } from '@app/app-types';

@Component({

...... saved some typing

})

export class StudentComponent implements OnInit {

@Input() student: Student;

refreshForm: EventEmitter<any>;

constructor(){}

ngOnInit(){

  this.refreshForm = new EventEmitter();

  }

}

这是单元测试

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

import {StudentComponet} from './student-component';

describe('StudentComponet', () => {

  let component: StudentComponent;

  let fixture: ComponentFixture<StudentComponent>;

  

  beforeEach(async(() => {

  TestBed.configureTestingModule({

    declarations: [StudentComponent]

  }).compileComponents();

  }));

  

  beforeEach(() => {

    fixture = TestBed.createComponent(StudentComponent);

    component = fixture.componentInstance;

    fixture.detectChanges();

  });

  

  it('should create', () => {

  expect(component).toBeTruthy();

  })

  

  });