Add systemdunitproperty probe test returning incorrect result (IMHO should be true, but returns false).
Add example of test for systemdunitproperty probe returning unknown result
Add another failing systemdunitproperty probe test, which should pass

Because default.target should be enabled on common system.
Add (currently failing) test to check if value of sockets.target unit Wants property contains two or more values
Array type dbus properties are reported as one value per one element

If there is an array of arrays the internal elements are ", " delimited
as before. The non-nested elements are one value per one element.