Database testing strategies when your team does not own the database schema?

We're an SDET team testing a service that uses a database we don't own — the schema is managed by a platform team and changes without always notifying us. Current problem: when the platform team adds a NOT NULL column or changes a type, our test fixtures silently start inserting bad data and tests give false positives. Is there a standard approach to: 1. Detecting schema drift between our fixtures and the live schema? 2. Getting notified when schema changes affect our test data? 3. Making fixture data generation schema-aware? We use SQLAlchemy + alembic but don't control the migrations.