trial run

Từ điển Oxford Advanced Learner 8th

ˌtrial ˈrun [trial run] BrE NAmE (also ˌtest ˈrun) noun
a test of how well sth new works, so that you can see if any changes are necessary
•This year is a trial run for the new service, before it is officially introduced in 2011.
See also: ↑test run