Angular TestBed（使用Jasmine）将组件输出到Karma测试结果页面

Question

以下是非常简单的Angular组件：

import { Component } from "@angular/core";

@Component({
  template: '<h1 style="background: red">Why am I here?</h1>'
})
export class SubmissionFormComponent {

}

这是测试：

import { ComponentFixture, TestBed } from '@angular/core/testing';
import { SubmissionFormComponent } from './submission-form.component';

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

  beforeEach(() => {

    TestBed.configureTestingModule({
      declarations: [SubmissionFormComponent]
    }).compileComponents();

    fixture = TestBed.createComponent(SubmissionFormComponent);
  });

  it('true is Truthy', () => {
    expect(true).toBeTruthy();
  });
});

这是输出： Karma test results with Angular component output

组件模板文字“我为什么来这里？”输出到测试结果页面。

如果我评论测试线：

fixture = TestBed.createComponent(SubmissionFormComponent);

然后“为什么我在这里”消失了。为什么TestBed.createComponent将组件输出到Karma结果页面？