Use AssertJ-Swagger to validate an API implementation’s compliance

The Documentation Driven Contracts test pattern, useful for public APIs,by designing your API through documentation, you can easily get feedback and iterate your design before any development happens. Changes are easier and faster to make in documentation than they are in code. It validates using #isEqualTo and will validate that the design first documentation contract matches the implementation in its entirety.

Consumer contracts allow us to reflect on the business value being exploited at any point in a provider’s lifetime. By expressing and asserting expectations of a provider contract, consumer contracts effectively define which parts of that provider contract currently support the business value realized by the system, and which do not.

To read more about types of contracts & its characteristics,check out here!

The Consumer Driven Contracts test pattern, useful for internal microservice APIs, validates using #satisfiesContract and will validate that the implementation provides, at minimum, the requirements of the design first consumer contract. This pattern allows for extension points in the API resources, resource methods, and models.

AssertJ-Swagger library supports the Swagger v2.0 specification. assertj-swagger compares Swagger objects like Paths, Parameters and Definitions. It does not compare unimportant Swagger objects like info, descriptions or summaries.

Using assertj-swagger is simple. For example, if you are using Spring Boot and springfox or JAX-RS Swagger, you can validate your Swagger JSON in an integration/unit test.It would fail test if it finds differences between the implementation and the specification & if it finds missing resources, methods, models, or properties in the implementation which are required by the consumer specification.

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