Fix test failures for Firebird

Author: hazzik

src/NHibernate.Test/CfgTest/ConfigurationSerializationTests.cs

@@ -3,6 +3,8 @@
 using System.Runtime.Serialization.Formatters.Binary;
 using NHibernate.Cfg;
 using NHibernate.DomainModel;
+using NHibernate.Driver;
+using NHibernate.Engine;
 using NHibernate.Tool.hbm2ddl;
 using NUnit.Framework;
 
@@ -82,6 +84,18 @@ public void Basic_CRUD_should_work()
 				var p = session.Get<Parent>(parentId);
 				Assert.That(p, Is.Null);
 			}
+
+			if (((ISessionFactoryImplementor) sf).ConnectionProvider.Driver is FirebirdClientDriver fbDriver)
+			{
+				// Firebird will pool each connection created during the test and will marked as used any table
+				// referenced by queries. It will at best delays those tables drop until connections are actually
+				// closed, or immediately fail dropping them.
+				// This results in other tests failing when they try to create tables with same name.
+				// By clearing the connection pool the tables will get dropped. This is done by the following code.
+				// Moved from NH1908 test case, contributed by Amro El-Fakharany.
+				fbDriver.ClearPool(null);
+			}
+
 			export.Drop(true, true);
 		}
 	}

src/NHibernate.Test/Tools/hbm2ddl/SchemaMetadataUpdaterTest/SchemaMetadataUpdaterFixture.cs

@@ -248,7 +248,7 @@ public void CanWorkWithAutoQuoteTableAndColumnsAtStratup()
 				t.Commit();
 			}
 
-			new SchemaExport(configuration).Drop(false, false);
+			new SchemaExport(configuration).Drop(false, true);
 		}
 
 		[Test]