Function open_test_db_schema 

pub fn open_test_db_schema(
    store_dir: StoreDir,
    tables: Vec<SyncedTable>,
    migrations: Vec<Migration>,
) -> Database

The synthetic store’s schema and Database constructors, which the database layer owns and its own tests open directly. Like open_test_db but with an explicit synced set and migration ladder, for tests that exercise a different schema (gate tests).