This is the interface your chess engine will have to implement.
You can find the ChessGameTestInterface related classes and JUnit tests here.
Note: The tests at this location are not exhaustive.
Note: The tests use a ChessGameTestInterfaceFactory factory class to get an implementation of the ChessGameTestInterface. You will have to override the getTestInterface method to return your own implementation of the test interface.
Note: The chess engine is assumed not to be tied to the UI. This is the reason for using simple JUnit tests.