trial run

plural trial runs

1. An empirical test of the suitability or effectiveness of a method or object by running it at least once.

   1 more example

   Because most diesel failures can be traced to electrical faults, minor in themselves but often difficult to pin-point, any unscheduled halt during a trial run is often the signal for the frenzied unfolding of wiring diagrams and the appearance of an impressive array of voltmeters and circuit testers.

   1962 April, R. K. Evans, “The Acceptance Testing of Diesel Locomotives”, in Modern Railways, page 268

2. An empirical test of the suitability or capability of a person or actor by letting them perform at least once.