Fix a flaky test (#2255)

See #1594

Author: fredericDelaporte

src/NHibernate.Test/Async/NHSpecificTest/GH1594/Fixture.cs

@@ -62,8 +62,13 @@ public async Task ExecutionContextLocalValuesLeakAsync()
 			{
 				await (RunInTransactionAsync(session));
 				var localValuesCountAfterFirstCall = ExecutionContext.Capture().LocalValuesCount();
+				if (!localValuesCountAfterFirstCall.HasValue)
+					Assert.Ignore("Unable to get async local values count");
 				await (RunInTransactionAsync(session));
 				var localValuesCountAfterSecondCall = ExecutionContext.Capture().LocalValuesCount();
+				if (!localValuesCountAfterSecondCall.HasValue)
+					Assert.Ignore("Unable to get async local values count");
+
 				Assert.AreEqual(localValuesCountAfterFirstCall, localValuesCountAfterSecondCall);
 			}
 		}

src/NHibernate.Test/NHSpecificTest/GH1594/ExecutionContextExtensions.cs

@@ -5,16 +5,18 @@ namespace NHibernate.Test.NHSpecificTest.GH1594
 {
 	public static class ExecutionContextExtensions
 	{
-		public static int LocalValuesCount(this ExecutionContext c)
+		public static int? LocalValuesCount(this ExecutionContext c)
 		{
 #if NETFX
 			const string localValuesFieldName = "_localValues";
 #else			
 			const string localValuesFieldName = "m_localValues";
 #endif
 			var f = typeof(ExecutionContext).GetField(localValuesFieldName, System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
-			var d = (IDictionary) f.GetValue(c);
-			return d?.Count ?? 0;
+			// The property value may not implement IDictionary, especially when there is less than 4 values, but not only.
+			// So we may not be able to know anything about this count.
+			var d = f.GetValue(c) as IDictionary;
+			return d?.Count;
 		}
 	}
 }

src/NHibernate.Test/NHSpecificTest/GH1594/Fixture.cs

@@ -50,8 +50,13 @@ public void ExecutionContextLocalValuesLeak()
 			{
 				RunInTransaction(session);
 				var localValuesCountAfterFirstCall = ExecutionContext.Capture().LocalValuesCount();
+				if (!localValuesCountAfterFirstCall.HasValue)
+					Assert.Ignore("Unable to get async local values count");
 				RunInTransaction(session);
 				var localValuesCountAfterSecondCall = ExecutionContext.Capture().LocalValuesCount();
+				if (!localValuesCountAfterSecondCall.HasValue)
+					Assert.Ignore("Unable to get async local values count");
+
 				Assert.AreEqual(localValuesCountAfterFirstCall, localValuesCountAfterSecondCall);
 			}
 		}