Add - Functional tests for vanilla pip install and with --editable

[uncojohnco]

from pathlib import Path
import site
import runpy

# TODO: Have this behavior work  with both - vanilla "pip install" and with --editable

# Works with "pip install --editable ."
# root = Path(__file__).parent.parent
# filepath = str(root.joinpath('src/lss/lss_cli.py'))

# Works with "pip install ."
root = Path(site.getsitepackages()[0])  # TODO: This should be more robust...
filepath = str(root.joinpath('lss/lss_cli.py'))