Prompt

Implement contract testing between services.

<service_architecture>
{describe microservices and APIs}
</service_architecture>

<integration_points>
{list all service interactions}
</integration_points>

<current_testing>
{existing integration tests}
</current_testing>

Implement:
1. Contract definition format
2. Provider verification
3. Consumer testing
4. Contract versioning
5. Breaking change detection
6. CI/CD integration