test case 
noun Law
A case that sets a precedent for other cases involving the same question of law: figurative it was a test case for cooperation between the teams...
- Barristers have drawn up a legal opinion setting out a test case for a high court judicial review of the government's position.
- The appellant's action was a test case on which eleven other cases raising the same issues depended.
- In the course of his submissions the Solicitor-General referred to this appeal as a test case.