deduplicate ExtensionSet.TryMergeFieldFrom implementation, add test
diff --git a/csharp/src/Google.Protobuf.Test/ExtensionSetTest.cs b/csharp/src/Google.Protobuf.Test/ExtensionSetTest.cs
index 2607811..934b780 100644
--- a/csharp/src/Google.Protobuf.Test/ExtensionSetTest.cs
+++ b/csharp/src/Google.Protobuf.Test/ExtensionSetTest.cs
@@ -62,6 +62,22 @@
}
[Test]
+ public void TryMergeFieldFrom_CodedInputStream()
+ {
+ var message = new TestAllExtensions();
+ message.SetExtension(OptionalStringExtension, "abcd");
+
+ var input = new CodedInputStream(message.ToByteArray());
+ input.ExtensionRegistry = new ExtensionRegistry() { OptionalStringExtension };
+ input.ReadTag(); // TryMergeFieldFrom expects that a tag was just read and will inspect the LastTag value
+
+ ExtensionSet<TestAllExtensions> extensionSet = null;
+ // test the legacy overload of TryMergeFieldFrom that takes a CodedInputStream
+ Assert.IsTrue(ExtensionSet.TryMergeFieldFrom(ref extensionSet, input));
+ Assert.AreEqual("abcd", ExtensionSet.Get(ref extensionSet, OptionalStringExtension));
+ }
+
+ [Test]
public void TestEquals()
{
var message = new TestAllExtensions();
