make test:
    run all tests (default)

make clean:
    remove all sby workdirs

make test[_m_<mode>][_e_<engine>][_s_<solver>]:
    run all tests that use a specific mode, engine and solver

make <name>:
    run the test for <name>.sby

make refresh:
    do nothing apart from refreshing generated make rules

make help:
    show this help

running make in a subdirectory or prefixing the target with the subdirectory
limits the test selection to that directory