Angular Karma Jasmine Unit Test: TypeError: this.errorDialog.close is not a function

Question

I have following error during simple unit test in Angular/Jasmine/Karma.

TypeError: this.errorDialog.close is not a function

I have viewchild with close function. I would like to test close method.

TEST:

 it('closeErrorDialog',()=>{
    spyOn(component,'closeErrorDialog').and.callThrough();
    component.closeErrorDialog();
   });

Tested Method:

 @ViewChild('errorDialog') errorDialog: any;

 closeErrorDialog() {
    this.errorDialog.close();
  }

<custom-modal #errorDialog>
    <button style="margin-right: 300px;" id="clsbtn" custom-button data-kind="primary"
      (click)="closeError409Dialog()">clsoe</button>
</custom-modal>```

Could i ask you to help me or give me link to article or anything what can be helpful?