public void AddTreatmentMethod_PetInputParam_IncremantsTreatmentsCount()
 {
     var sut = new Pet();
     sut.Treatments.Count.ShouldEqual(0);
     sut.AddTreatment(new Treatment(Treatment.TreatmentEnum.Hydration));
     sut.Treatments.Count.ShouldEqual(1);
 }