increase coverage of GeneratedMessageTest
diff --git a/csharp/src/Google.Protobuf.Test/MessageParsingHelpers.cs b/csharp/src/Google.Protobuf.Test/MessageParsingHelpers.cs
new file mode 100644
index 0000000..d629d9c
--- /dev/null
+++ b/csharp/src/Google.Protobuf.Test/MessageParsingHelpers.cs
@@ -0,0 +1,86 @@
+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2015 Google Inc. All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#endregion
+
+using NUnit.Framework;
+using System;
+using Google.Protobuf.Buffers;
+using System.Buffers;
+
+namespace Google.Protobuf
+{
+ public static class MessageParsingHelpers
+ {
+ public static void AssertReadingMessage<T>(MessageParser<T> parser, byte[] bytes, Action<T> assert) where T : IMessage<T>
+ {
+ var parsedStream = parser.ParseFrom(bytes);
+
+ // Load content as single segment
+ var parsedBuffer = parser.ParseFrom(new ReadOnlySequence<byte>(bytes));
+ assert(parsedBuffer);
+
+ // Load content as multiple segments
+ parsedBuffer = parser.ParseFrom(ReadOnlySequenceFactory.CreateWithContent(bytes));
+ assert(parsedBuffer);
+
+ assert(parsedStream);
+ }
+
+ public static void AssertReadingMessageThrows<TMessage, TException>(MessageParser<TMessage> parser, byte[] bytes)
+ where TMessage : IMessage<TMessage>
+ where TException : Exception
+ {
+ Assert.Throws<TException>(() => parser.ParseFrom(bytes));
+
+ Assert.Throws<TException>(() => parser.ParseFrom(new ReadOnlySequence<byte>(bytes)));
+ }
+
+ public static void AssertRoundtrip<T>(MessageParser<T> parser, T message, Action<T> additionalAssert = null) where T : IMessage<T>
+ {
+ var bytes = message.ToByteArray();
+
+ // Load content as single segment
+ var parsedBuffer = parser.ParseFrom(new ReadOnlySequence<byte>(bytes));
+ Assert.AreEqual(message, parsedBuffer);
+ additionalAssert?.Invoke(parsedBuffer);
+
+ // Load content as multiple segments
+ parsedBuffer = parser.ParseFrom(ReadOnlySequenceFactory.CreateWithContent(bytes));
+ Assert.AreEqual(message, parsedBuffer);
+ additionalAssert?.Invoke(parsedBuffer);
+
+ var parsedStream = parser.ParseFrom(bytes);
+
+ Assert.AreEqual(message, parsedStream);
+ additionalAssert?.Invoke(parsedStream);
+ }
+ }
+}
\ No newline at end of file
