trial run
The performance of some task or action as a means of testing or rehearsing something. They want everyone to show up tomorrow for a trial run of the ceremony. See if you can do a trial run on the laptop before you buy it from him.
a trial run
COMMON A trial run is something that you do to practise before you do it at a more important time. They will use their match with the highly-rated Saracens forwards on Wednesday as a trial run for what awaits them on February 26.
a ˌtrial ˈrun
a first try at doing something, to test it or for practice: Take the car for a trial run before you buy it.