tzurot-testing

Unit tests with mocked dependencies isolate code under test by replacing external services. Use Vitest's mocking utilities to mock Discord.js, Redis, Prisma, or AI providers, then write assertions against the isolated behavior. This ensures fast, deterministic tests without hitting real databases or APIs.

Fake timers control time-dependent operations in Vitest, eliminating flakiness and dramatically accelerating test execution. Configure fake timers in your test setup, advance time programmatically within tests, and assertions run instantly instead of waiting for real delays.

Promise rejection handling in Vitest prevents unhandled rejection warnings and ensures robust error assertions. Wrap async operations, use `.rejects` matchers, and structure assertions to catch both synchronous throws and promise rejections, validating error behavior comprehensively.

Integration tests validate service interactions while mocking external dependencies like Discord, BullMQ, Redis, and Prisma. Define mock factories alongside tests, structure colocated test files, and simulate realistic workflows without coupling to actual service implementations or infrastructure.

Unit, integration, and component tests share core Vitest patterns but differ in scope and mocking strategy. Unit tests mock dependencies tightly, integration tests mock external services only, and component tests validate UI behavior. One framework handles all three with adjusted isolation levels.