Contract testing
We have seen that integration tests are also used to test external services, services that are probably not in our code base and that may not even be maintained by us. You then create a stub, or mock, that returns a “fake” answer, based on documentation or, often, on the real answers exchanged at runtime between the two services. But what happens if something changes, if one of the two changes the contract? How do you make sure that the mock we’ve created is really a representation of the outside service? Contract testing helps us.
Contract testing aims to ensure compatibility and agreement between different services or components within a distributed system. It is particularly useful in scenarios such as microservices architectures where different services need to communicate seamlessly. In contract testing, services communicate with each other based on well-defined interfaces or contracts. These contracts outline how data is exchanged, specify...
