Pytest

This is a comprehensive testing guide laser-focused on customer support systems, not just generic pytest tutorials. It covers the stuff that actually matters when you're building ticketing platforms: testing multi-tenant isolation, SLA calculations, async webhook deliveries, and all those gnarly external integrations with email providers and CRMs. The fixture patterns are solid, especially the session-scoped database setup with automatic rollbacks. What's refreshing is how it acknowledges the specific pain points of support systems like PII validation, real-time features, and compliance requirements. If you're building anything in the customer support or help desk space with FastAPI and PostgreSQL, this gives you battle-tested patterns instead of making you figure out async mocking and parametrization from scratch.