diff --git a/S7.Net.UnitTest/S7.Net.UnitTest.csproj b/S7.Net.UnitTest/S7.Net.UnitTest.csproj
index 487efa8..0a14d88 100644
--- a/S7.Net.UnitTest/S7.Net.UnitTest.csproj
+++ b/S7.Net.UnitTest/S7.Net.UnitTest.csproj
@@ -80,6 +80,7 @@
     <Compile Include="S7NetTestsSync.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Helpers\TestLongStruct.cs" />
+    <Compile Include="TypeTests\ClassTests.cs" />
     <Compile Include="TypeTests\DateTimeTests.cs" />
     <Compile Include="TypeTests\StringExTests.cs" />
     <Compile Include="TypeTests\StringTests.cs" />
diff --git a/S7.Net.UnitTest/TypeTests/ClassTests.cs b/S7.Net.UnitTest/TypeTests/ClassTests.cs
new file mode 100644
index 0000000..ba99c2c
--- /dev/null
+++ b/S7.Net.UnitTest/TypeTests/ClassTests.cs
@@ -0,0 +1,33 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using S7.Net.Types;
+
+namespace S7.Net.UnitTest.TypeTests
+{
+    [TestClass]
+    public class ClassTests
+    {
+        [TestMethod]
+        public void GetClassSizeTest()
+        {
+            Assert.AreEqual(Class.GetClassSize(new TestClassUnevenSize(1, 1)), 6);
+            Assert.AreEqual(Class.GetClassSize(new TestClassUnevenSize(2, 15)), 6);
+            Assert.AreEqual(Class.GetClassSize(new TestClassUnevenSize(2, 16)), 6);
+            Assert.AreEqual(Class.GetClassSize(new TestClassUnevenSize(2, 17)), 8);
+            Assert.AreEqual(Class.GetClassSize(new TestClassUnevenSize(3, 15)), 8);
+            Assert.AreEqual(Class.GetClassSize(new TestClassUnevenSize(3, 17)), 10);
+        }
+
+        private class TestClassUnevenSize
+        {
+            public bool Bool { get; set; }
+            public byte[] Bytes { get; set; }
+            public bool[] Bools { get; set; }
+
+            public TestClassUnevenSize(int byteCount, int bitCount)
+            {
+                Bytes = new byte[byteCount];
+                Bools = new bool[bitCount];
+            }
+        }
+    }
+}