You'll need sbt. Then:

sbt "run-main rovers.RoversApp input.txt"

You can run the tests with:

sbt test

Most of the domain model is in the object domain. Design choices are mostly documented there. The main test efforts are for this module, as it is the business module. I used property based testing to test the moves.

To parse the input in a functional style, I used atto. I designed the parser using the REPL, so unlike the domain model, there are few tests because there is only one function in this module.

Finally, there is the io package. This package contains file reading and console writing stuff: algebras along with the corresponding interpreters. I chose to not write any test for this module, as implementation is straightforward.

The program itself is in RoversApp. It is designed using the tagless final encoding, allowing efficient effect handling, and can be tested -- see this as an integration test -- using stub interpreters (typically using Id as F).