public void Post() { //Arrange var controller = new ItemsController(mockContext.Object); var items = controller.Get(); controller.Request = new HttpRequestMessage(); controller.Configuration = new HttpConfiguration(); var enumerable = items as Item[] ?? items.ToArray(); var item0 = enumerable.FirstOrDefault(x => x.ItemId == 0); var item1 = enumerable.FirstOrDefault(x => x.ItemId == 1); //Act var result1 = controller.Post(item0); var result2 = controller.Post(item1); //Assert Assert.AreEqual(result1.StatusCode, HttpStatusCode.OK); Assert.AreEqual(result2.StatusCode, HttpStatusCode.BadRequest); }