An alternate view: if you really care about case, double quote the database
on creation, as per your "e.g.":
create database "testDB";
At that point, your psql connection will work. But as with all
non-lowercase objects, extra care will be needed and it will need to be
quoted in some contexts. It's so much easier to just leave database,
schema, table, and column names as lowercase. Then everything just works.
Cheers,
Greg