All you're testing in all of these is the hints behavior.  If someone was running the spec tests on GCE this test in particular would actually fail since it would really run the plugin and would find the metadata server and/or DMI information.  You should at least wrap all of the current tests with stubbing has_dmi? and has_metadata? to be false.   It would also probably be good to unit test has_dmi? and has_metadata? in isolation.