angular - 如何对垫子步进器进行组件测试？

Question

我有以下垫步步骤：

<button mat-raised-button (click)="isLinear = !isLinear" id="toggle-linear">
 {{!isLinear ? 'Enable linear mode' : 'Disable linear mode'}}
</button>
<mat-horizontal-stepper [linear]="isLinear" #stepper>
<mat-step [stepControl]="firstFormGroup">
<form [formGroup]="firstFormGroup">
  <ng-template matStepLabel>Fill out your name</ng-template>
  <mat-form-field>
    <mat-label>Name</mat-label>
    <input matInput placeholder="Last name, First name" formControlName="firstCtrl" required>
  </mat-form-field>
  <div>
    <button mat-button matStepperNext>Next</button>
  </div>
 </form>
</mat-step>
<mat-step [stepControl]="secondFormGroup" label="Fill out your address">
<form [formGroup]="secondFormGroup">
  <mat-form-field>
    <mat-label>Address</mat-label>
    <input matInput formControlName="secondCtrl" placeholder="Ex. 1 Main St, New York, NY"
           required>
  </mat-form-field>
  <div>
    <button mat-button matStepperPrevious>Back</button>
    <button mat-button matStepperNext>Next</button>
  </div>
  </form>
 </mat-step>

如何进行单元测试以检查是否单击了下一步按钮，它实际上移动到下一个索引？