The EphemeralForTestRecordStore uses a mutex to control access to its _data->records member. However, EphemeralForTestRecordStore::Cursor and ::ReverseCursor get a direct reference to this member and do not lock the mutex when accessing it.

Furthermore, these classes cache an iterator to the structure, which is a std::map; in the case of a rollback these iterators will be invalid, and in the case of a delete they might be.