public void GetByModelIDAsync_ModelNotFound_ThrowsNull()
        {   //arrange
            var  repository = new Mock <IVehicleModelRepository>();
            Guid modelIdArg = Guid.Empty;

            repository
            .Setup(m => m.GetByModelIDAsync(It.Is <Guid>(id => id == modelIdArg)))
            .ReturnsAsync(() => null);


            var classForTesting = new VehicleModelService(repository.Object);
            //act
            var result = classForTesting.GetByModelIDAsync(modelIdArg);

            //assert
            result.Should().BeNull();
        }
        public async void GetByModelIDAsync_Success_ReturnNotNull()
        {   //arrange
            var  repository = new Mock <IVehicleModelRepository>();
            Guid modelIdArg = Guid.NewGuid();

            repository
            .Setup(m => m.GetByModelIDAsync(It.Is <Guid>(id => id == modelIdArg)))
            .ReturnsAsync(() => new VehicleModel());

            var classForTesting = new VehicleModelService(repository.Object);

            //act
            var result = await classForTesting.GetByModelIDAsync(modelIdArg);

            //assert

            result.Should().NotBeNull();
        }