Full three part naming helps the query optimizer recognize and reuse queries in the execution plan cache. Queries with unqualified names, including those in stored procedures, have to be fully parsed and processed each time they execute because the name resolution is based on that session's user's default schema.

So if you can use fully qualified names in your environment, it gives much better performance.

If you need a test database, you might consider using another SQL Server instance, a virtual machine, or testing on "developer" workstations.