Interesting that on this modern FADEC kit power checks during taxi are a little more tricky as you cant fail the ECUs and cycle the props at anything other than power idle - mind you easy to dispense with before you move off the pan.
I do the power checks on the Twin Star on the taxy. Just give it a bit of beans, pull the leavers back to idle and press the test buttons until the tests are complete. Easy
(for the record on FADEC Tdi's FADEC doesn't thrash the engines up to 2000 rpm for the power checks)