public void CreateCarValidationTest(string modelName, string brand, string carClass, int?seats)
        {
            //Arrange
            var mockUow = new Mock <IUnitOfWork>();

            mockUow.Setup(a => a.Cars.Create(It.IsAny <Car>()));

            //Act
            var service = new RentService(mockUow.Object);

            //Assert
            Assert.Throws <ValidationException>(
                () =>
                service.CreateCar(new CarDTO {
                ModelName = modelName, Brand = brand, Class = carClass, Seats = seats
            }));
        }