From Longman Dictionary of Contemporary Englishdry runˌdry ˈrun noun [countable] PRACTISE/PRACTICEan event that is a practice for a more important event Both the parties are treating the local elections as a dry run.
Examples from the Corpus
dry run• BIn some ways, the learning center provides a dry run for the workaday world.• Apprenticeships enable companies to screen future workers and give them a dry run before selecting the best for long-term employment.• They were there for a countdown dry run. 