DATA, the path to the data files for testing specified in
tests/lib/test_appliance.py is hard coded
tests/data. This makes it impossible to run the tests from any other directory than the top of the repository. You cannot do:
cd tests/data edit some_test.code python ../lib/test_yaml.py
DATA = __file__.rsplit("/", 2) + "/data"
allows you to start the tests from any directory (not tested on WIndows, might need os.sep instead of "/")