Flushing the session should expire the instance and it's children

[fayazkhan]

This test currently fails.

    def test_session_expire(self):
        node = self.session.query(self.model).filter(self.model.ppk == 4).one()
        node.move_after('1')
        self.session.flush()
        # self.session.expire(node)
        self.assertEqual(node.tree_id, 2)
        self.assertEqual(node.parent_id, None)

Expiring the node solves the problem. So shouldn't the after_flush_post_exec listener be expiring those attributes too?
A simpler solution would be to update those values from mptt_before_update.

[uralbash]

Thank you for your issue, it,s very similar to #30
I'll add a check tree_id in after_flush_post_exec

[fayazkhan]

Shouldn't all the children also be expired there?
Something similar to what you're doing for the parents?

[uralbash]

All the children expired with parent after flush. See example 62779c9

[uralbash]

I created a new branch path-33 for this issue, until I can not pass this test https://github.com/ITCase/sqlalchemy_mptt/blob/path-33/sqlalchemy_mptt/tests/tree_testing_base.py#L1732