Unit testing using pytest

Hi all:

In the github repository I see a tests folder in this path /plotly.py/tree/master/packages/python/plotly/plotly)/tests/ that contains several test folders with a variety of tests.
How do I use this test folder to run tests?
My plotly installation did not come with this folder, so Iโ€™m trying to figure out how I can use pytest to run through these tests.

Thank you!