Haven't worked the NG, but on the wide bodies the procedure is to set the opposite engine to ~70% N1 to limit the side torque on the nose gear before running the test engine to a climb or TO power setting. There are also minimum fuel loads required prior to running to high power.
However most 'high power' engine tests no longer go to full takeoff power - with FADEC we've been able to use something around max climb for most 'high power' testing.