add C# sanity test

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

@@ -91,6 +91,7 @@
     <Compile Include="ContextPropagationTest.cs" />
     <Compile Include="MetadataTest.cs" />
     <Compile Include="PerformanceTest.cs" />
+    <Compile Include="SanityTest.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <ItemGroup>

src/csharp/Grpc.Core.Tests/SanityTest.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.Collections.Generic;
+using System.IO;
+using System.Reflection;
+using Grpc.Core;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+using NUnit.Framework;
+
+namespace Grpc.Core.Tests
+{
+    public class SanityTest
+    {
+        /// <summary>
+        /// Because we depend on a native library, sometimes when things go wrong, the
+        /// entire NUnit test process crashes. To be able to track down problems better,
+        /// the NUnit tests are run by run_tests.py script in a separate process per test class.
+        /// The list of tests to run is stored in src/csharp/tests.json.
+        /// This test checks that the tests.json file is up to date by discovering all the
+        /// existing NUnit tests in all test assemblies and comparing to contents of tests.json.
+        /// </summary>
+        [Test]
+        public void TestsJsonUpToDate()
+        {
+            var testClasses = DiscoverAllTestClasses();
+            string testsJson = GetTestsJson();
+
+            // we don't have a JSON parser at hand, but check that the test class
+            // name is contained in the file instead.
+            foreach (var className in testClasses) {
+                Assert.IsTrue(testsJson.Contains(className),
+                    string.Format("Test class \"{0}\" is missing in C# tests.json file", className));
+            }
+        }
+
+        /// <summary>
+        /// Gets list of all test classes obtained by inspecting all the test assemblies.
+        /// </summary>
+        private List<string> DiscoverAllTestClasses()
+        {
+            var assemblies = GetTestAssemblies();
+
+            var testClasses = new List<string>();
+            foreach (var assembly in assemblies)
+            {
+                foreach (var t in assembly.GetTypes())
+                {
+                    foreach (var m in t.GetMethods())
+                    {
+                        var attributes = m.GetCustomAttributes(typeof(NUnit.Framework.TestAttribute), true);
+                        if (attributes.Length > 0)
+                        {
+                            testClasses.Add(t.FullName);
+                            break;
+                        }
+
+                    }
+                }
+            }
+            testClasses.Sort();
+            return testClasses;
+        }
+
+        private string GetTestsJson()
+        {
+            var assemblyDir = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
+            var testsJsonFile = Path.Combine(assemblyDir, "..", "..", "..", "tests.json");
+
+            return File.ReadAllText(testsJsonFile);
+        }
+
+        private List<Assembly> GetTestAssemblies()
+        {
+            var result = new List<Assembly>();
+            var executingAssembly = Assembly.GetExecutingAssembly();
+
+            result.Add(executingAssembly);
+
+            var otherAssemblies = new[] {
+                "Grpc.Examples.Tests",
+                "Grpc.HealthCheck.Tests",
+                "Grpc.IntegrationTesting"
+            };
+            foreach (var assemblyName in otherAssemblies)
+            {
+                var location = executingAssembly.Location.Replace("Grpc.Core.Tests", assemblyName);
+                result.Add(Assembly.LoadFrom(location));
+            }
+            return result;
+        }
+    }
+}