{"id":8417,"date":"2025-02-19T07:27:08","date_gmt":"2025-02-19T07:27:08","guid":{"rendered":"https:\/\/kognivera.com\/?p=8417"},"modified":"2025-03-05T13:04:35","modified_gmt":"2025-03-05T07:34:35","slug":"contract-testing-with-pact-spock-and-gradle","status":"publish","type":"post","link":"https:\/\/kognivera.com\/staging\/blog\/contract-testing-with-pact-spock-and-gradle\/","title":{"rendered":"Contract testing with Pact, Spock and gradle"},"content":{"rendered":"\t\t
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Building a microservice architecture to effectively run and operate resilient distributed services is hard. Especially, when you run into a use case that needs inter-service communication. Domain Driven Design principles help in identifying clear boundaries where each microservice is responsible for a well-defined subset of business logic. But at some point, you realise that the microservice you’re building still needs to communicate with another service for data. Typically this data resides within another service and read\/write operations on this data can be performed either synchronously using REST APIs, gRPC etc. or asynchronously using message brokers.<\/p>

When two independently deployable services within a system communicate with each other, testing the integration becomes vital before we go to production. Integration testing is a widely used testing strategy and a fundamental step in the testing pyramid<\/a>. However, in the case of microservices, regardless of services being backward compatible, integration tests do not take into account – the changes that occur in API contracts\/definitions with changing requirements once these services are deployed to Production or even during the course of development. Enter Contract testing.<\/p>

The key idea of contract testing is to independently test the sender (generally referred to as “provider”) and the receiver (or “consumer”) using the same contract. The contract definition can be shared by either storing it locally on the consumer and provider OR by hosting it on a server and making it available to both sides via a network.<\/p>

The contract essentially defines how the two services communicate. It can be defined either in the provider service or in the consumer service. When a service is used by multiple unknown consumers typically in case of SaaS API, provider-driven<\/b> approach is beneficial. In a microservice architecture, where all services within the domain are known and the provider needs to comply with the consumer’s requirements, consumer-driven<\/b> approach is a better fit.<\/p>

There are many popular frameworks available like Spring Cloud Contract, Hypertest, Pact for contract testing services in Java applications. In this article, we will be looking at Pact as a tool for contract testing inter-service HTTP communication in a Spring-boot microservices application. Pact is a platform-independent library that follows a consumer-driven contract testing approach.<\/p>

Let’s consider a use case in an e-commmerce system – communication between checkout service and shipping service.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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