Fix flaky tests by increasing the timeout for a task to complete. (#82)

Also realized that the TaskAssert helper class wasn't actually testing
anything, so I fixed that. Then I needed to fix another test that wasn't
testing correctly.

test/Microsoft.VisualStudio.Web.BrowserLink.Test/DelayConnectingHttpSocketAdapterTest.cs

@@ -349,7 +349,7 @@ namespace Microsoft.VisualStudio.Web.BrowserLink
 
             _createdAdapter = new MockHttpSocketAdapter();
 
-            return null;
+            return Task.FromResult((IHttpSocketAdapter)null);
         }
 
         private Task HandleAsciiResponse(byte[] buffer, int offset, int count)

test/Microsoft.VisualStudio.Web.BrowserLink.Test/ScriptInjectionFilterStreamTest.cs

@@ -292,7 +292,7 @@ namespace Microsoft.VisualStudio.Web.BrowserLink
             TaskAssert.NotCompleted(writeTask, "Should be waiting for server to respond");
 
             // Act II - Wait for the request to time out
-            System.Threading.Thread.Sleep(1100);
+            writeTask.Wait(2000);
 
             // Assert
             TaskAssert.Completed(writeTask, "Write should complete when server fails to respond");

test/Microsoft.VisualStudio.Web.BrowserLink.Test/TaskAssert.cs

@@ -48,7 +48,7 @@ namespace Microsoft.VisualStudio.Web.BrowserLink
                 ThrowFailure(
                     task.Exception,
                     GetMethodFailureMessage(nameof(NotFaulted)),
-                    FormatMessage(task.Exception), 
+                    FormatMessage(task.Exception),
                     FormatMessage(messageFormat, args));
             }
         }
@@ -81,15 +81,7 @@ namespace Microsoft.VisualStudio.Web.BrowserLink
         {
             exception = UnwrapException(exception);
 
-            // TODO: Add this condition back with the right exception type
-            //if (exception is AssertFailedException)
-            //{
-            //    return null;
-            //}
-            //else
-            //{
-                return String.Format("{0}: {1}.", exception.GetType().Name, exception.Message);
-            //}
+            return exception.ToString();
         }
 
         private static string FormatMessage(string messageFormat, params object[] messageArgs)
@@ -113,22 +105,7 @@ namespace Microsoft.VisualStudio.Web.BrowserLink
         {
             string failureMessage = String.Join(" ", failureMessages.Where(x => !String.IsNullOrWhiteSpace(x)));
 
-            if (exception != null)
-            {
-                exception = UnwrapException(exception);
-
-                // TODO: Add this code back with the right exception type
-                //if (exception is AssertFailedException)
-                //{
-                //    throw exception;
-                //}
-
-                //throw new AssertFailedException(failureMessage, exception);
-            }
-            else
-            {
-                //throw new AssertFailedException(failureMessage);
-            }
+            Assert.True(false, failureMessage);
         }
 
         private static Exception UnwrapException(Exception exception)