make test problem
## ❓ Questions & Help
Hello all,

I recently installed this library/module and wanted to run a test with: `make test`      
However, things do not go right and I got the following message:

> python -m pytest -n auto --dist=loadfile -s -v ./tests/
> /System/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python: No module named pytest
> make: *** [test] Error 1

I'm using macOS X Catalina, with Python3.7 (3.7.5), pytest is installed. 
(I have no clue why it returns an error on Py2.7 )

Thanks in advance
