1 files changed, 13 insertions, 0 deletions
diff --git a/src/ProtocolBuffers.Test/DynamicMessageTest.cs b/src/ProtocolBuffers.Test/DynamicMessageTest.cs
index edcce38e..2f3fefa8 100644
--- a/src/ProtocolBuffers.Test/DynamicMessageTest.cs
+++ b/src/ProtocolBuffers.Test/DynamicMessageTest.cs
@@ -32,6 +32,7 @@ using Google.ProtocolBuffers.TestProtos;
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 using NUnit.Framework;
+using System;
 
 namespace Google.ProtocolBuffers {
   [TestFixture]
@@ -57,6 +58,18 @@ namespace Google.ProtocolBuffers {
     }
 
     [Test]
+    public void DoubleBuildError() {
+      DynamicMessage.Builder builder = DynamicMessage.CreateBuilder(TestAllTypes.Descriptor);
+      builder.Build();
+      try {
+        builder.Build();
+        Assert.Fail("Should have thrown exception.");
+      } catch (InvalidOperationException e) {
+        // Success.
+      }
+    }
+
+    [Test]
     public void DynamicMessageSettersRejectNull() {
       IBuilder builder = DynamicMessage.CreateBuilder(TestAllTypes.Descriptor);
       reflectionTester.AssertReflectionSettersRejectNull(builder);