In this chapter we introduced the Google Guice dependency injection framework on which Xtext relies. You should now be aware of how easy it is to inject custom implementations consistently throughout the framework. You also learned how to customize some basic runtime and IDE concepts for a DSL.
The next chapter shows how to perform unit testing for languages implemented in Xtext. Test driven development is an important programming technique which will make your implementations more reliable, resilient to changes of the libraries, and will allow you to program quickly.