The in-memory back end should be tested as part of the standard regression tests.
The following is a good start:
o simple create / boot test
o create in-memory db, backup, restore with default storage engine, modify, restore with createFrom into memory again
o add the functional test(s) written by Cheng
o more unit tests
On a longer term, we should consider to add the possibility to run all or a subset of the general regression tests with the in-memory back end.