(PDOC-5) Test host classes and 3x functions

Add tests for the remaining two Puppet-specific handlers that were
not tested in the previous commit. Specifically, add tests for the
3.x function handler and the host class handler.
(PDOC-5) Remove unneeded test case

Remove an unneeded test case. Since it would be caught even in a very
basic system, an automated test case is not needed.