test_nodetypes: change testInvertibles to a TestCase (for easier testing of individiual methods)
test_nodetypes: change testInvertibles to a TestCase (for easier testing of individiual methods)

juggernate/pymel,assumptionsoup/pymel,leonsooi/pymel,david-lassonde-adsk/pymel,shrtcww/pymel,AtonLerin/pymel,david-lassonde-adsk/pymel,juggernate/pymel,leonsooi/pymel,AtonLerin/pymel,assumptionsoup/pymel,shrtcww/pymel