How to test a dynamic reactive form in Angular?

I am new on Angular and I have been trying to test this component:

    <ng-container *ngIf="parentProps" >
      <div *ngIf="parentProps.editMode === 1" >
        <br />
        <form class="detalhes-container">
          <ng-container *ngFor="let info of parentProps.applicationsData; let i = index; trackBy: trackByFn">
            <div
              class="detalhes-bloco"
              *ngIf="parentProps.activeStepIndexSkills === i"
              [formGroup]="parentProps.masterFormEdit[i]"
            >
              <p class="teste" >teste</p>

              <div
                class="detalhes-conhecimento-container"
                formGroupName="conhecimento"
              ></div>
            </div>
          </ng-container>
        </form>
       </div>
    </ng-container>

It is working great, but when it comes to test it I just don't get how to do.

The only thing I need here is to reach the p element with the class teste, however I always get this error: Error: formGroup expects a FormGroup instance. Please pass one in.

It seems that I have to instantiate the formGroup and I tried to do that in the spec.ts file, but it just doesn't change anything.

Maybe it is worth mentioning, parentProps.masterFormEdit is an array with a undetermined number of objects and each index (i) is a form. I am receiving it through @input.

I have read and watched a bunch of tutorials, but none of them could give me the answer I need, or maybe they did, but since I am a beginner I may just not have seen.

Anyways, anyone could help me, please? I am going crazy with that already.

Thank you!