call displayServers with no parameters and investigate the things that it returns. This depends on there being at least one server defined, as do some other tests in this module.
call displayServers with a position that does not exist and make sure that we get none back.
call displayServers with a position that does exist and make sure that we get at least one back.
call displayServers with a type that does not exist and make sure that we get none back.
call displayServers with a type that does exist and make sure that we get at least one back.
call displayServers with a variety of both positions and types and verify that we get either something or nothing back.
these are not test methods, but they help me write them.
returns a position value for which at least one server exists
returns a type value for which at least one server exists
returns a position and type for a server