fix skipped Test: TraceProviderSdkTest.TracerProviderSdkInvokesSampli…

…ngWithCorrectParameters (#2809)

test/OpenTelemetry.Tests/Trace/TracerProviderSdkTest.cs

@@ -34,7 +34,7 @@ public TracerProviderSdkTest()
             Activity.DefaultIdFormat = ActivityIdFormat.W3C;
         }
 
-        [Fact(Skip = "Get around GitHub failure")]
+        [Fact]
         public void TracerProviderSdkInvokesSamplingWithCorrectParameters()
         {
             var testSampler = new TestSampler();
@@ -101,10 +101,15 @@ public void TracerProviderSdkInvokesSamplingWithCorrectParameters()
             using (var fromInvalidW3CIdParent =
                 activitySource.StartActivity("customContext", ActivityKind.Client, "InvalidW3CIdParent"))
             {
-                // OpenTelemetry ActivityContext does not support
-                // non W3C Ids. Starting activity with non W3C Ids
-                // will result in no activity being created.
-                Assert.Null(fromInvalidW3CIdParent);
+                // Verify that StartActivity returns an instance of Activity.
+                Assert.NotNull(fromInvalidW3CIdParent);
+
+                // Verify that the TestSampler was invoked and received the correct params.
+                Assert.Equal(fromInvalidW3CIdParent.TraceId, testSampler.LatestSamplingParameters.TraceId);
+
+                // OpenTelemetry ActivityContext does not support non W3C Ids.
+                Assert.Null(fromInvalidW3CIdParent.ParentId);
+                Assert.Equal(default(ActivitySpanId), fromInvalidW3CIdParent.ParentSpanId);
             }
         }