Stop trying to connect if the test host exits unexpectedly (#1853)

* Fixed the issue 1689.
Taking into consideration host launch failures while waiting to setup connection, so we bail out sooner.

Author: singhsarab

src/Microsoft.TestPlatform.CommunicationUtilities/TestRequestSender.cs

@@ -146,9 +146,12 @@ public bool WaitForRequestHandlerConnection(int connectionTimeout, CancellationT
                 EqtTrace.Verbose("TestRequestSender.WaitForRequestHandlerConnection: waiting for connection with timeout: {0}", connectionTimeout);
             }
 
-            var waitIndex = WaitHandle.WaitAny(new WaitHandle[] { this.connected.WaitHandle, cancellationToken.WaitHandle }, connectionTimeout);
+            // Wait until either connection is successful, handled by connected.WaitHandle
+            // or operation is cancelled, handled by cancellationToken.WaitHandle
+            // or testhost exits unexpectedly, handled by clientExited.WaitHandle
+            var waitIndex = WaitHandle.WaitAny(new WaitHandle[] { this.connected.WaitHandle, cancellationToken.WaitHandle, this.clientExited.WaitHandle }, connectionTimeout);
 
-            // Return true if wait is because of waitHandle.
+            // Return true if connection was successful.
             return waitIndex == 0;
         }
 

src/Microsoft.TestPlatform.CrossPlatEngine/Client/ProxyOperationManager.cs

@@ -155,7 +155,8 @@ public virtual bool SetupChannel(IEnumerable<string> sources)
                     connTimeout *= 5;
                 }
 
-                // Wait for a timeout for the client to connect.
+                // If TestHost does not launch then throw exception
+                // If Testhost launches, wait for connection.
                 if (!this.testHostLaunched ||
                     !this.RequestSender.WaitForRequestHandlerConnection(connTimeout * 1000, this.CancellationTokenSource.Token))
                 {
@@ -300,7 +301,6 @@ private void TestHostManagerHostLaunched(object sender, HostProviderEventArgs e)
         private void TestHostManagerHostExited(object sender, HostProviderEventArgs e)
         {
             this.testHostProcessStdError = e.Data;
-
             this.RequestSender.OnClientProcessExit(this.testHostProcessStdError);
 
             this.testHostExited.Set();

test/Microsoft.TestPlatform.CommunicationUtilities.UnitTests/TestRequestSenderTests.cs

@@ -98,14 +98,33 @@ public void WaitForRequestHandlerConnectionShouldNotConnectIfExceptionWasThrownB
         }
 
         [TestMethod]
-        public void WaitForRequestHandlerConnectionWithInfiniteTimeoutShouldReturnImmediatelyWhenCancellationRequested()
+        public void WaitForRequestHandlerConnectionWithTimeoutShouldReturnImmediatelyWhenCancellationRequested()
         {
             var cancellationTokenSource = new CancellationTokenSource();
             cancellationTokenSource.Cancel();
 
-            var connected = this.testRequestSender.WaitForRequestHandlerConnection(-1, cancellationTokenSource.Token);
+            var connectionTimeout = 5000;
+            var watch = System.Diagnostics.Stopwatch.StartNew();
+            var connected = this.testRequestSender.WaitForRequestHandlerConnection(connectionTimeout, cancellationTokenSource.Token);
+            watch.Stop();
 
             Assert.IsFalse(connected);
+            Assert.IsTrue(watch.ElapsedMilliseconds < connectionTimeout);
+        }
+
+        [TestMethod]
+        public void WaitForRequestHandlerConnectionWithTimeoutShouldReturnImmediatelyIfHostExitedUnexpectedly()
+        {
+            var cancellationTokenSource = new CancellationTokenSource();
+            this.testRequestSender.OnClientProcessExit("DummyError");
+
+            var connectionTimeout = 5000;
+            var watch = System.Diagnostics.Stopwatch.StartNew();
+            var connected = this.testRequestSender.WaitForRequestHandlerConnection(connectionTimeout, cancellationTokenSource.Token);
+            watch.Stop();
+
+            Assert.IsFalse(connected);
+            Assert.IsTrue(watch.ElapsedMilliseconds < connectionTimeout);
         }
 
         [TestMethod]