public void Verify_That_WriteXmlAsync_Without_Definition_Set_Throws_SerializationException()
        {
            using var memoryStream = new MemoryStream();
            using var writer       = XmlWriter.Create(memoryStream, new XmlWriterSettings { Indent = true });
            var attributeValueReal = new AttributeValueBoolean();

            var cts = new CancellationTokenSource();

            Assert.That(
                async() => await attributeValueReal.WriteXmlAsync(writer, cts.Token),
                Throws.Exception.TypeOf <SerializationException>()
                .With.Message.Contains("The Definition property of an AttributeValueBoolean may not be null"));
        }
        public void Verify_That_WriteXmlAsync_Throws_Exception_when_cancelled()
        {
            using var memoryStream = new MemoryStream();
            using var writer       = XmlWriter.Create(memoryStream, new XmlWriterSettings { Indent = true });

            var attributeValueReal = new AttributeValueBoolean
            {
                Definition = new AttributeDefinitionBoolean()
            };

            var cts = new CancellationTokenSource();

            cts.Cancel();

            Assert.That(
                async() => await attributeValueReal.WriteXmlAsync(writer, cts.Token),
                Throws.Exception.TypeOf <OperationCanceledException>());
        }