an occasion when you try doing something or using something before you really need to use it, to make sure everything works properly 〔对新事物的〕初步试验，试行
Examples from the Corpus
test run• The visiting locomotives will progressively arrive during the Steam Festival and after a test run will be used on weekend passenger services.• This short crossing would be a test run.• Switch off, disconnect and cover A test run is important.• Burfoot took a pair of Puma Concepts for a test run and said he liked them.• The cameras were in court for a test run, not for broadcasting.• The generator failed three times during its test run.
From Longman Business Dictionary
test-runˈtest-run noun [countableC]
an occasion when a new machine, piece of equipment, or procedure is tested to find out whether it works correctly
Fire during a test-run seriously damaged an experimental Japanese supertrain.