Dry run
Meaning
A rehearsal done before the real event.
Usage
Used when testing procedures without consequence.
Origin & History
Origins and dates here are approximate summaries. Many idioms have disputed or unknown origins, and not every date has been checked against a historical dictionary, so treat specific dates and stories as a starting point rather than a citation.
Military drills done without live ammo.
Generalized in planning language by the 20th century.