Most of the mechanisms of a DSL implemented in Xtext can be tested with plain Java JUnit tests without a UI environment. However, when testing UI features, tests need a running Eclipse.
Eclipse provides a specific launch configuration, "JUnit Plug-in Test", which executes JUnit tests with a running Eclipse.
Implementing tests for the UI concepts might be tricky, since usually you will need to write code to set up Eclipse workbench infrastructures such as projects, files, and so on. Xtext provides some base classes for testing UI concepts, which do most of the job for you so that you can simply test specific features without having to worry about the setup steps.
All the UI tests we implement in this section are created in the project org.example.entities.ui.tests.
