Contract Testing

<default_to_action> When testing API contracts or microservices:

1. DEFINE consumer expectations (what consumers actually need)
2. VERIFY provider fulfills contracts (Pact verification)
3. DETECT breaking changes before deployment (CI/CD integration)
4. VERSION APIs semantically (breaking = major bump)
5. MAINTAIN backward compatibility for supported versions

Quick Contract Testing Steps:

• Consumer: Define expected request/response pairs
• Provider: Verify against all consumer contracts
• CI/CD: Block deploys that break contracts
• Versioning: Document supported versions and deprecation

Critical Success Factors:

• Consumers own the contract (they define what they need)
• Provider must pass all consumer contracts before deploy