public async Task ValidateGivenPet(int petId)
        {
            _mockRepository.Setup(x => x.GetPetAsync(petId, It.IsAny <bool>())).ReturnsAsync(_pets.FirstOrDefault(p => p.PetId == petId));

            var actionResult = await _sut.GetPetAsync(petId, true);

            if (actionResult is NotFoundResult)
            {
                Assert.Null(_pets.FirstOrDefault(p => p.PetId == petId));
            }
            else
            {
                var value = ((Microsoft.AspNetCore.Mvc.ObjectResult)actionResult).Value;
                var model = Assert.IsType <PetViewModel>(value);

                Assert.NotNull(model);
                Assert.Equal(2, model.People.Count);
            }
        }