Changed testing script for custom py command

use -py "python_command"

bin/testing.py

@@ -10,8 +10,7 @@ It additionally installs all dependencies from a '../requirements.txt' via pip.
 Use command line argument '-w' to run on windows.
 '''
 
-PY = 'py' if (len(sys.argv) > 1 and sys.argv[1] == '-w') else 'python3.7' # use -w to run on windows
-
+PY = sys.argv[2] if (len(sys.argv) > 1 and sys.argv[1] == '-py') else 'python3.7' # use -py to use your own python command
 ROOT = pathlib.Path(__file__).parent.parent.absolute()
 TESTS_FOLDER_NAME = os.path.normpath("/tests")