### Question:
ActorCrn extends ActorBase { public static Builder builder() { return new Builder(); } ActorCrn(Builder builder); String getActorCrn(); static Builder builder(); @Override String toString();  }### Answer:
@Test void emptyBuilderConstructionTest() { ThrowingCallable constructor = () -> ActorCrn.builder().build(); assertConstruction(constructor, false, IllegalArgumentException.class, "Actor user must be a valid CRN"); }