Mapper contributing guidelines

Everything in the main contribution guidelines also applies to the mapper. This file adds specific guidelines for the mapper.

Testing

There are two ways to test the mapper:

Unit tests

These tests reside here in the mapper-processor module. They run javac in-process with the mapper's annotation processor configured. Each test creates its own input source code using the JavaPoet DSL.

For an example, refer to any subclass of MapperProcessorTest (DaoFactoryMethodGeneratorTest is one of them).

We don't fully validate the generated code, because it would be too much overhead to maintain those checks anytime something changes. Therefore those tests should not try to cover semantic aspects of the mapper, but instead focus on:

• errors and warnings, e.g. which method signatures are valid for a particular annotation, and what happens otherwise;
• presence and naming of the generated files for a particular input source.

Integration tests

These tests reside in the usual integration-tests module. They cover the whole cycle: the module contains annotated sources and runs the mapper processor as part of its build; the tests use the generated code to interact with a CCM cluster.

For an example, see GetEntityIT.