public void ShouldConvertCustomIStickerMessageToStickerMessage()
            {
                var message = new TestStickerMessage();

                var stickerMessage = StickerMessage.Convert(message);

                Assert.AreNotEqual(message, stickerMessage);

                Assert.AreEqual("PackageId", stickerMessage.PackageId);
                Assert.AreEqual("StickerId", stickerMessage.StickerId);
            }
            public void ShouldThrowExceptionWhenStickerIdIsNull()
            {
                var message = new StickerMessage()
                {
                    PackageId = "PackageId"
                };

                ExceptionAssert.Throws <InvalidOperationException>("The sticker id cannot be null.", () =>
                {
                    StickerMessage.Convert(message);
                });
            }
            public void ShouldPreserveInstanceWhenValueIsStickerMessage()
            {
                var message = new StickerMessage()
                {
                    PackageId = "PackageId",
                    StickerId = "StickerId"
                };

                var stickerMessage = StickerMessage.Convert(message);

                Assert.AreSame(message, stickerMessage);
            }