@deeky666 you are right, i haven't taken into account the platforms with support for identity columns or that emulate it with sequences, i'll get on to it now.

@kimhemsoe 42 tests triggered this with Informix. The problem was that I did not implement the method of the abstract class in the platform class and Informix doesn't allow insert nulls into identity columns; some of them are:

	Functional\LifecycleCallbackTest::testCascadedEntitiesCallsPrePersist
	Functional\OneToManyUnidirectionalAssociationTest::testPersistOwning_InverseCascade
	Functional\OrderedCollectionTest::testLazyManyToManyCollection_IsRetrievedWithOrderByClause
	Functional\OrderedCollectionTest::testLazyOneToManyCollection_IsRetrievedWithOrderByClaus
	...

tell me if you want the complete list.