To run the BDD test suite you need to install behave and a few other Python
packages first. The easiest way to do that is to use pip:
$ pip3 install -r requirements.txt
Afterwards you should be able to just run behave:
$ behave
If for some reason the behave binary wasn't put into your PATH you can run
the installed package directly:
$ python3 -mbehave
Please check the behave documentation for the available command line options.