I have a custom matcher, very basic, and I don’t know how to write a unit test for this (minimum coverage is mandatory on the project).

Should I mock completely FormControl and Form to test each value of submitted/invalid/dirty/touched?
That looks like a lot of mocking, is there anything in Angular to ease that kind of test?

/**
 * Error when invalid control is dirty, touched, or submitted.
 */
export class ShowOnChangeErrorStateMatcher implements ErrorStateMatcher {
  isErrorState(control: FormControl | null, form: FormGroupDirective | NgForm | null): boolean {
    if (!control) {
      return false;
    }

    const isSubmitted = form?.submitted ?? false;
    return control.invalid && (control.dirty || control.touched || isSubmitted);
  }
}