Rely on three levels testing of Contracts when translating your products:

Unit tests will need to be fully rewritten as they depend on the Contracts Language API version custom types and API. Use the contracts_api Python package available in the Contracts SDK for unit tests.

Contracts Simulation tests are Contracts Language API version agnostic tests that test the product's behaviour, features and business logic. Minimal or no changes should be required for these tests when translating your products.

E2E tests are Contract tests that are triggered using the Core API endpoints. To test your translated products end-to-end, you should open new accounts and plans and then test their behaviour by triggering various accounts journeys over time.