test: Add test for mixinClass with static properties

Increasing code coverage.

Change-Id: I1017484388c785f9ece90ae6fb5d1847bc449ab3
test: Add test for getObjectValues with inherited properties

Increasing code coverage. Also remove bogus test for numbers
passed to this function; Garbage in, garabage out.

Change-Id: I6ca8943c23e49e49a2fba16f13b19c5855489309