The project purpose is in the wiki If you share some of my experiences then you might find the code here useful.

Project structure

These are the 4 projects.

sheep-dog-test - Demonstrates how to add a jar to an Xtext project. This has the code that is reused in the Xtext editors in this repo.
sheepdogxtextcukeplugin.parent - This is the Eclipse plugin that the testers use to write their test cases.
sheep-dog-dev - This converts the test cases into UML models and converts those into Cucumber and Java or anything else. I'll try wrapping this in other build tools in the future.
sheep-dog-maven-plugin - This is a Maven plug-in that's just a wrapper around sheep-dog-dev. The developer can make a batch script to do a git pull and run this to refresh the test data/automation that they need to continue their red-green-refactor cycles.

How to

I've tried to document and develop these projects for folks who are new to Xtext and Maven plugin development. I'd read the pages in this order.