Check out the --no-owner and/or --no-acl flags when performing the dump. These eliminate the statements that set and/or alter ownership of database objects.
For use in a test server where the username of the test-server database is different than the username on the production server *and* where you don't have lots of roles with different ownership and permissions across your database you should be fine.
Or create role(s) on your test database that match those on the production database. This may require updating pg_hba.conf on the test database.
Cheers,
Steve