public async Task DeleteTruck_Exists_ReturnsOk()
        {
            // create model
            var model = new Model();

            model.Description = Guid.NewGuid().ToString();

            IActionResult actionResult = await _modelController.PostModel(model);

            var modelCreatedResult = actionResult as CreatedAtActionResult;

            Assert.IsNotNull(modelCreatedResult);
            Assert.AreEqual(201, modelCreatedResult.StatusCode);
            model.ModelId = Convert.ToInt32(modelCreatedResult.RouteValues["id"]);

            // create truck
            var truck = new Truck();

            truck.Chassis = Guid.NewGuid().ToString();
            truck.Year    = Convert.ToInt16(new Random().Next(1900, 2019));
            truck.Model   = model;

            actionResult = await _truckController.PostTruck(truck);

            var createdResult = actionResult as CreatedAtActionResult;

            Assert.IsNotNull(createdResult);
            Assert.AreEqual(201, createdResult.StatusCode);

            // delete truck
            actionResult = await _truckController.DeleteTruck(truck.TruckId);

            var okResult = actionResult as OkObjectResult;

            Assert.IsNotNull(okResult);
            Assert.AreEqual(200, okResult.StatusCode);

            Assert.Pass();
        }