The more complex our rules become, the more important it is to have tests for them and keep them organized as much as possible. In this section, we will discuss how we organized our example projects for keeping our rules, their tests, and related classes in a structure that can be easily maintained.

We recommend this way of structuring the projects so that each of them keeps a very well-defined scope, set of dependencies, and they can be tested independently. You should keep all the application infrastructural code (user interfaces, system integration, services, and so on) in separate Maven modules as well, therefore, the infrastructure can be maintained in separate cycles from the business knowledge that tends to be updated more frequently by the business needs.

The example repository contains a high-level parent project that is composed by each individual chapter modules. Each individual chapter contains the following three main modules: