lessphp uses phpunit for it's tests
InputTest.php iterates through all the less files in
inputs/, compiles them,
then compares the result with the respective file in
From the root you can run
make to run all the tests.
Clones twitter bootsrap, compiles it with lessc and lessphp, cleans up results with sort.php, and outputs diff. To run it, you need to have git and lessc installed.