add positional args and a (commented out) debugger option for tox tes…

…tenv

tox.ini

@@ -7,7 +7,11 @@ env_list = lint, type, py38
 description = run unit tests
 deps =
     pytest>=3
-commands = pytest -v tests/
+commands = pytest -v tests/ {posargs}
+# NOTE: to use interactive debugger, comment the above line and uncomment the following two lines
+#    pytest-pudb
+#commands = pytest --pudb -v tests/ {posargs}
+
 
 [testenv:lint]
 description = run linters