diff --git a/csharp/src/Google.Protobuf.Test/UnknownFieldSetTest.cs b/csharp/src/Google.Protobuf.Test/UnknownFieldSetTest.cs
index 0663465808b2..886937d70620 100644
--- a/csharp/src/Google.Protobuf.Test/UnknownFieldSetTest.cs
+++ b/csharp/src/Google.Protobuf.Test/UnknownFieldSetTest.cs
@@ -40,6 +40,18 @@ namespace Google.Protobuf
 {
     public class UnknownFieldSetTest
     {
+        public class Data
+        {
+            public static System.Collections.IEnumerable Messages
+            {
+                get
+                {
+                    yield return SampleMessages.CreateFullTestAllTypesProto2();
+                    yield return SampleMessages.CreateFullTestAllTypes();
+                }
+            }
+        }
+
         [Test]
         public void EmptyUnknownFieldSet()
         {
@@ -61,24 +73,23 @@ public void MergeUnknownFieldSet()
         }
 
         [Test]
-        public void TestMergeCodedInput()
+        [TestCaseSource(typeof(Data), "Messages")]
+        public void TestMergeCodedInput(IMessage message)
         {
-            var message = SampleMessages.CreateFullTestAllTypesProto2();
             var emptyMessage = new TestEmptyMessage();
             emptyMessage.MergeFrom(message.ToByteArray());
             Assert.AreEqual(message.CalculateSize(), emptyMessage.CalculateSize());
             Assert.AreEqual(message.ToByteArray(), emptyMessage.ToByteArray());
 
-            var newMessage = new Proto2.TestAllTypes();
-            newMessage.MergeFrom(emptyMessage.ToByteArray());
+            var newMessage = message.Descriptor.Parser.ParseFrom(emptyMessage.ToByteArray());
             Assert.AreEqual(message, newMessage);
             Assert.AreEqual(message.CalculateSize(), newMessage.CalculateSize());
         }
 
         [Test]
-        public void TestMergeMessage()
+        [TestCaseSource(typeof(Data), "Messages")]
+        public void TestMergeMessage(IMessage message)
         {
-            var message = SampleMessages.CreateFullTestAllTypesProto2();
             var emptyMessage = new TestEmptyMessage();
             var otherEmptyMessage = new TestEmptyMessage();
             emptyMessage.MergeFrom(message.ToByteArray());
@@ -89,9 +100,9 @@ public void TestMergeMessage()
         }
 
         [Test]
-        public void TestEquals()
+        [TestCaseSource(typeof(Data), "Messages")]
+        public void TestEquals(IMessage message)
         {
-            var message = SampleMessages.CreateFullTestAllTypesProto2();
             var emptyMessage = new TestEmptyMessage();
             var otherEmptyMessage = new TestEmptyMessage();
             Assert.AreEqual(emptyMessage, otherEmptyMessage);
@@ -102,9 +113,9 @@ public void TestEquals()
         }
 
         [Test]
-        public void TestHashCode()
+        [TestCaseSource(typeof(Data), "Messages")]
+        public void TestHashCode(IMessage message)
         {
-            var message = SampleMessages.CreateFullTestAllTypesProto2();
             var emptyMessage = new TestEmptyMessage();
             int hashCode = emptyMessage.GetHashCode();
             emptyMessage.MergeFrom(message.ToByteArray());
@@ -112,7 +123,8 @@ public void TestHashCode()
         }
 
         [Test]
-        public void TestClone()
+        [TestCaseSource(typeof(Data), "Messages")]
+        public void TestClone(IMessage message)
         {
             var emptyMessage = new TestEmptyMessage();
             var otherEmptyMessage = new TestEmptyMessage();
@@ -120,7 +132,6 @@ public void TestClone()
             Assert.AreEqual(emptyMessage.CalculateSize(), otherEmptyMessage.CalculateSize());
             Assert.AreEqual(emptyMessage.ToByteArray(), otherEmptyMessage.ToByteArray());
 
-            var message = SampleMessages.CreateFullTestAllTypesProto2();
             emptyMessage.MergeFrom(message.ToByteArray());
             otherEmptyMessage = emptyMessage.Clone();
             Assert.AreEqual(message.CalculateSize(), otherEmptyMessage.CalculateSize());
@@ -128,9 +139,9 @@ public void TestClone()
         }
 
         [Test]
-        public void TestDiscardUnknownFields()
+        [TestCaseSource(typeof(Data), "Messages")]
+        public void TestDiscardUnknownFields(IMessage message)
         {
-            var message = SampleMessages.CreateFullTestAllTypesProto2();
             var goldenEmptyMessage = new TestEmptyMessage();
             byte[] data = message.ToByteArray();
             int fullSize = message.CalculateSize();