The tests require the fake-sys directory which comes from https://github.com/ddemidov/ev3dev-lang-fake-sys

If you have already cloned the ev3dev-lang-python repo but do not have the fake-sys directory use git submodule init to get it. If you have not already cloned the ev3dev-lang-python repo you can use the --recursive option when you git clone. Example:

$ git clone --recursive https://github.com/rhempel/ev3dev-lang-python.git

To run the tests do:

$ ./api_tests.py

Commands used to copy the /sys/class node:

$ node=lego-sensor/sensor0
$ mkdir -p ./${node}
$ cp -P --copy-contents -r /sys/class/${node}/* ./${node}/