diff --git a/MQTT-SDK/test/Cumulocity.SDK.MQTT.Tests/MQTTTopicValidatorTest.cs b/MQTT-SDK/test/Cumulocity.SDK.MQTT.Tests/MQTTTopicValidatorTest.cs
new file mode 100644
index 0000000..31a2e52
--- /dev/null
+++ b/MQTT-SDK/test/Cumulocity.SDK.MQTT.Tests/MQTTTopicValidatorTest.cs
@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Xunit;
+using Cumulocity.SDK.MQTT.Util;
+
+namespace Cumulocity.SDK.MQTT.Tests
+{
+    public class MQTTTopicValidatorTest
+    {
+        [Fact]
+        public void IsTopicValidForPublishTest()
+        {
+            Assert.False(MqttTopicValidator.IsTopicValidForPublish(""));
+            Assert.False(MqttTopicValidator.IsTopicValidForPublish(null));
+            Assert.False(MqttTopicValidator.IsTopicValidForPublish("UnknownTopic"));
+            Assert.False(MqttTopicValidator.IsTopicValidForPublish("s/dt"));
+            Assert.False(MqttTopicValidator.IsTopicValidForPublish("s/dcr"));
+            Assert.False(MqttTopicValidator.IsTopicValidForPublish("s/ds"));
+            Assert.True(MqttTopicValidator.IsTopicValidForPublish("s/us"));
+            Assert.True(MqttTopicValidator.IsTopicValidForPublish("s/ul"));
+            Assert.True(MqttTopicValidator.IsTopicValidForPublish("s/ucr"));
+        }
+
+
+        [Fact]
+        public void IsTopicValidForSubscribeTest()
+        {
+            Assert.False(MqttTopicValidator.IsTopicValidForSubscribe(""));
+            Assert.False(MqttTopicValidator.IsTopicValidForSubscribe(null));
+            Assert.False(MqttTopicValidator.IsTopicValidForSubscribe("UnknownTopic"));
+            Assert.False(MqttTopicValidator.IsTopicValidForSubscribe("s/ul"));
+            Assert.False(MqttTopicValidator.IsTopicValidForSubscribe("s/ucr"));
+            Assert.False(MqttTopicValidator.IsTopicValidForSubscribe("s/us"));
+            Assert.True(MqttTopicValidator.IsTopicValidForSubscribe("s/dt"));
+            Assert.True(MqttTopicValidator.IsTopicValidForSubscribe("s/dcr"));
+            Assert.True(MqttTopicValidator.IsTopicValidForSubscribe("s/ds"));
+        }
+
+    }
+}