make sure async test wont be silently skipped with old NUnit

src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj

@@ -68,6 +68,7 @@
     <Compile Include="ChannelOptionsTest.cs" />
     <Compile Include="Internal\TimespecTest.cs" />
     <Compile Include="TimeoutsTest.cs" />
+    <Compile Include="NUnitVersionTest.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <ItemGroup>

src/csharp/Grpc.Core.Tests/NUnitVersionTest.cs

+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// 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 System;
+using System.Threading;
+using System.Threading.Tasks;
+using Grpc.Core;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+using NUnit.Framework;
+
+namespace Grpc.Core.Tests
+{
+    /// <summary>
+    /// Tests if the version of nunit-console used is sufficient to run async tests.
+    /// </summary>
+    public class NUnitVersionTest
+    {
+        private int testRunCount = 0;
+
+        [TestFixtureTearDown]
+        public void Cleanup()
+        {
+            if (testRunCount != 2)
+            {
+                Console.Error.WriteLine("You are using and old version of NUnit that doesn't support async tests and skips them instead. " +
+                "This test has failed to indicate that.");
+                Console.Error.Flush();
+                Environment.Exit(1);
+            }
+        }
+
+        [Test]
+        public void NUnitVersionTest1()
+        {
+            testRunCount++;
+        }
+
+        // Old version of NUnit will skip this test
+        [Test]
+        public async Task NUnitVersionTest2()
+        {
+            testRunCount ++;
+            await Task.Delay(10);
+        }
+
+
+    }
+}

tools/run_tests/run_csharp.sh

@@ -32,6 +32,8 @@ set -ex
 
 CONFIG=${CONFIG:-opt}
 
+NUNIT_CONSOLE="mono packages/NUnit.Runners.2.6.4/tools/nunit-console.exe"
+
 if [ "$CONFIG" = "dbg" ]
 then
   MSBUILD_CONFIG="Debug"
@@ -46,6 +48,7 @@ root=`pwd`
 cd src/csharp
 
 export LD_LIBRARY_PATH=$root/libs/$CONFIG
-nunit-console -labels "$1/bin/$MSBUILD_CONFIG/$1.dll"
+
+$NUNIT_CONSOLE -labels "$1/bin/$MSBUILD_CONFIG/$1.dll"