Trying to prevent the weird test timing issues.

Added xunit runner config file to prevent test parallelization.
Changed formatting, cleared the buffer and checked for the right named object, and added locking.
Subtracted 50 milliseconds from the test start time to compensate for the build lab reporting earlier timestamps for telemetry items.

test/FunctionalTestUtils/TelemetryTestsBase.cs

@@ -5,6 +5,7 @@
     using System.Linq;
     using System.Net.Http;
     using System.Reflection;
+    using System.Runtime.CompilerServices;
     using System.Threading;
     using System.Threading.Tasks;
     using Microsoft.ApplicationInsights.DataContracts;
@@ -20,38 +21,45 @@
     public abstract class TelemetryTestsBase
     {
         protected const int TestTimeoutMs = 10000;
+        private object noParallelism = new object();
 
+        [MethodImpl(MethodImplOptions.NoOptimization)]
         public void ValidateBasicRequest(InProcessServer server, string requestPath, RequestTelemetry expected)
         {
-            DateTimeOffset testStart = new DateTimeOffset(Stopwatch.GetTimestamp(), TimeSpan.Zero);
-            var timer = Stopwatch.StartNew();
+            lock (noParallelism)
+            {
+                // Subtract 50 milliseconds to hack around strange behavior on build server where the RequestTelemetry.Timestamp is somehow sometimes earlier than now by a few milliseconds.
+                expected.Timestamp = DateTimeOffset.Now.Subtract(TimeSpan.FromMilliseconds(50));
+                server.BackChannel.Buffer.Clear();
+                Stopwatch timer = Stopwatch.StartNew();
 
-            var httpClientHandler = new HttpClientHandler();
-            httpClientHandler.UseDefaultCredentials = true;
+                var httpClientHandler = new HttpClientHandler();
+                httpClientHandler.UseDefaultCredentials = true;
 
-            Task<HttpResponseMessage> task;
-            using (var httpClient = new HttpClient(httpClientHandler, true))
-            {
-                task = httpClient.GetAsync(server.BaseHost + requestPath);
-                task.Wait(TestTimeoutMs);
-            }
+                Task<HttpResponseMessage> task;
+                using (HttpClient httpClient = new HttpClient(httpClientHandler, true))
+                {
+                    task = httpClient.GetAsync(server.BaseHost + requestPath);
+                    task.Wait(TestTimeoutMs);
+                }
 
-            timer.Stop();
-            server.Dispose();
+                timer.Stop();
+                server.Dispose();
 
-            var actual = server.BackChannel.Buffer.OfType<RequestTelemetry>().Single();
+                RequestTelemetry actual = server.BackChannel.Buffer.OfType<RequestTelemetry>().Where(t => t.Name == expected.Name).Single();
+                server.BackChannel.Buffer.Clear();
 
-            Assert.Equal(expected.ResponseCode, actual.ResponseCode);
-            Assert.Equal(expected.Name, actual.Name);
-            Assert.Equal(expected.Success, actual.Success);
-            Assert.Equal(expected.Url, actual.Url);
-            InRange(actual.Timestamp, testStart, new DateTimeOffset(Stopwatch.GetTimestamp(), TimeSpan.Zero));
-            Assert.True(actual.Duration < timer.Elapsed, "duration");
+                Assert.Equal(expected.ResponseCode, actual.ResponseCode);
+                Assert.Equal(expected.Name, actual.Name);
+                Assert.Equal(expected.Success, actual.Success);
+                Assert.Equal(expected.Url, actual.Url);
+                InRange(actual.Timestamp, expected.Timestamp, DateTimeOffset.Now);
+                Assert.True(actual.Duration < timer.Elapsed, "duration");
+            }
         }
 
         public void ValidateBasicException(InProcessServer server, string requestPath, ExceptionTelemetry expected)
         {
-            DateTimeOffset testStart = DateTimeOffset.Now;
             var httpClientHandler = new HttpClientHandler();
             httpClientHandler.UseDefaultCredentials = true;
 

test/WebApiShimFw46.FunctionalTests/project.json

@@ -6,7 +6,7 @@
     "delaySign": true,
     "preserveCompilationContext": true,
     "copyToOutput": {
-      "includeFiles": [ "config.json" ]
+      "includeFiles": [ "config.json", "xunit.runner.json" ]
     }
   },
   "testRunner": "xunit",

test/WebApiShimFw46.FunctionalTests/xunit.runner.json

@@ -0,0 +1,4 @@
+{
+    "parallelizeAssembly": false,
+    "parallelizeTestCollections": false
+}