# Buf detects breaking changes in your .proto files:
$ buf breaking --against .git#branch=main
proto/user/v1/service.proto:10:3: Field "2" on message "User" changed type from "string" to "int32".
Integration Testing
Spin up real server (Docker container)
Use real gRPC client to call it
Verify responses and side effects (DB state, events published)
Test error cases (invalid input, timeouts, unavailable dependencies)
Testcontainers Pattern
// Start dependencies in Docker, run tests against them:// 1. Start Redis container// 2. Start your gRPC service container (connected to Redis)// 3. Create gRPC client pointing to service container// 4. Run test scenarios// 5. Tear down containers