NH-2176 - crutch for delayed disposal. Only possible fix IMO: cease delaying session disposal when an ambient transaction is ongoing.

Author: fredericDelaporte

src/NHibernate.Test/NHSpecificTest/DtcFailures/DtcFailuresFixture.cs

@@ -502,7 +502,7 @@ public void CanUseSessionOutsideOfScopeAfterScope([Values(false, true)] bool exp
 				Assert.DoesNotThrow(() => count = s.Query<Person>().Count(), "Failed using the session after scope.");
 				if (count != 1)
 					// We are not testing that here, so just issue a warning. Do not use DodgeTransactionCompletionDelayIfRequired
-					// before  previous assert. We want to ascertain the session is usable in any cases.
+					// before previous assert. We want to ascertain the session is usable in any cases.
 					Assert.Warn("Unexpected entity count: {0} instead of {1}. The transaction seems to have a delayed commit.", count, 1);
 			}
 		}

src/NHibernate.Test/TestCase.cs

@@ -16,6 +16,7 @@
 using NUnit.Framework.Interfaces;
 using System.Text;
 using static NUnit.Framework.TestContext;
+using System.Threading;
 
 namespace NHibernate.Test
 {
@@ -221,13 +222,26 @@ private bool CheckSessionsWereClosed()
 			var allClosed = true;
 			foreach (var session in _openedSessions)
 			{
-				session.GetSessionImplementation().TransactionContext?.WaitOne();
-				if (session.IsOpen)
+				var txContext = session.GetSessionImplementation().TransactionContext;
+				txContext?.WaitOne();
+				if (!session.IsOpen)
+					continue;
+
+				if (txContext?.ShouldCloseSessionOnDistributedTransactionCompleted ?? false)
 				{
-					log.Error($"Test case didn't close session {session.GetSessionImplementation().SessionId}, closing");
-					allClosed = false;
-					session.Close();
+					// Delayed rollback not having lock from prepare phase? Give it a chance to complete.
+					Thread.Sleep(100);
+					txContext.WaitOne();
+					if (!session.IsOpen)
+					{
+						log.Warn($"Test case had a delayed close of session {session.GetSessionImplementation().SessionId}.");
+						continue;
+					}
 				}
+
+				log.Error($"Test case didn't close session {session.GetSessionImplementation().SessionId}, closing");
+				allClosed = false;
+				session.Close();
 			}
 
 			return allClosed;