How to Test Microservice Integration with Pact

Microservice integration testing presents challenges as services need to operate together despite the modular nature of microservices, making traditional end-to-end testing less valuable due to complexity and false negatives. Consumer-Driven Contract (CDC) testing offers a solution by allowing consumers to define expected service interactions, shifting integration responsibilities to providers and enhancing collaboration across geographically dispersed teams. CDC testing frameworks like Pact and Spring Cloud Contract facilitate this process by enabling the definition and verification of service contracts within CI/CD pipelines. Pact, in particular, supports multiple programming languages, making it suitable for polyglot microservices environments. In practice, developers create consumer tests that specify interactions with provider services, generating a contract file that is shared and verified by the provider, ensuring that service interactions remain consistent and reliable. This approach supports continuous delivery and short feedback loops while maintaining service integrity despite independent development cycles.