I copied the test from single table case, as description points out.
The only change which I was forced to do is about the declared type of source and target fields of the NodeLink entity.
Currently (I think) we don't support association to polymorphic entities, using TABLE_PER_CLASS inheritance strategy.
Because we don't support even queries or loading on polymorphic entities using TABLE_PER_CLASS inheritance strategy.
So we couldn't using the super class Node as a field type for table per class inheritance strategy test version.