public void TestMergeMessage()
{
var message = new TestAllExtensions();
message.SetExtension(OptionalBoolExtension, true);
var other = new TestAllExtensions();
Assert.AreNotEqual(message, other);
Assert.AreNotEqual(message.CalculateSize(), other.CalculateSize());
other.MergeFrom(message);
Assert.AreEqual(message, other);
Assert.AreEqual(message.CalculateSize(), other.CalculateSize());
}