test case
noun [ C ]
LAW ukusa case in a court of law or another situation that will be used as an example when other similar cases are considered in the future:
be/serve as a test case (to do sth) The trial is a test case to establish what liability bankers should have in mergers and acquisitions.
be seen as a test case for/of sth The new proposals are seen as a test case of the Commission's support for free markets.
The two associations are bringing a legal test case against the current policy on work permits.