Go Integration Testing with Testcontainers

When to Use This Skill

• Writing integration tests that need real infrastructure (databases, caches, message queues)
• Testing data access layers against actual databases instead of mocks
• Verifying message queue or cache integrations
• Testing database migrations and schema changes
• Ensuring tests work against production-like environments in CI/CD

Core Principles

1. Real Infrastructure Over Mocks - Use actual databases/services in containers, not mocks
2. Test Isolation - Each test gets fresh containers or clean data via snapshots
3. Automatic Cleanup - testcontainers.CleanupContainer(t, ctr) handles lifecycle
4. Idiomatic Go - Table-driven tests, t.Helper(), t.Cleanup(), subtests
5. Context Propagation - Pass context.Context to all container operations
6. Port Randomization - Containers use random ports to avoid conflicts