Add tests to improve code coverage (#187)

* DbColumn and ReliableConnection tests

* More retry connection tests

* More tests

* Fix broken peek definition integration tests

* Fix test bug

* Add a couple batch tests

* Add some more tests

* More tests for code coverage.

* Validation and Diagnostic tests

* A few more tests

* A few mote test changes.

* Update file path tests to run on Windows only

test/Microsoft.SqlTools.ServiceLayer.Test/Messaging/MessageDispatcherTests.cs

@@ -0,0 +1,88 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using System.Threading.Tasks;
+using Microsoft.SqlTools.ServiceLayer.Hosting.Protocol;
+using Microsoft.SqlTools.ServiceLayer.Hosting.Protocol.Channel;
+using Microsoft.SqlTools.ServiceLayer.Hosting.Protocol.Contracts;
+using Moq;
+using Xunit;
+
+namespace Microsoft.SqlTools.ServiceLayer.Test.Messaging
+{
+    public class MessageDispatcherTests
+    {
+        [Fact]
+        public void SetRequestHandlerWithOverrideTest()
+        {           
+            RequestType<int, int> requestType = RequestType<int, int>.Create("test/requestType");            
+            var dispatcher = new MessageDispatcher(new Mock<ChannelBase>().Object);
+            dispatcher.SetRequestHandler<int, int>(
+                requestType,
+                (i, j) => 
+                { 
+                    return Task.FromResult(0);
+                },
+                true);
+            Assert.True(dispatcher.requestHandlers.Count > 0);            
+        }
+
+        [Fact]
+        public void SetEventHandlerTest()
+        {           
+            EventType<int> eventType = EventType<int>.Create("test/eventType");            
+            var dispatcher = new MessageDispatcher(new Mock<ChannelBase>().Object);
+            dispatcher.SetEventHandler<int>(
+                eventType,
+                (i, j) => 
+                { 
+                    return Task.FromResult(0);
+                });
+            Assert.True(dispatcher.eventHandlers.Count > 0);            
+        }
+
+        [Fact]
+        public void SetEventHandlerWithOverrideTest()
+        {           
+            EventType<int> eventType = EventType<int>.Create("test/eventType");            
+            var dispatcher = new MessageDispatcher(new Mock<ChannelBase>().Object);
+            dispatcher.SetEventHandler<int>(
+                eventType,
+                (i, j) => 
+                { 
+                    return Task.FromResult(0);
+                },
+                true);
+            Assert.True(dispatcher.eventHandlers.Count > 0);            
+        }
+
+        [Fact]
+        public void OnListenTaskCompletedFaultedTaskTest()
+        {           
+            Task t = null;
+            
+            try
+            {
+                t = Task.Run(() => 
+                { 
+                    throw new Exception();
+                });            
+                t.Wait();
+            }
+            catch
+            {                
+            }
+            finally
+            {
+                bool handlerCalled = false;
+                var dispatcher = new MessageDispatcher(new Mock<ChannelBase>().Object);
+                dispatcher.UnhandledException += (s, e) => handlerCalled = true;       
+                dispatcher.OnListenTaskCompleted(t);
+                Assert.True(handlerCalled);   
+            }
+        }
+    }
+}