Don't bother installing anything into the venv just to run flake8.

erikrose · erikrose · commit db3618e391d8 · 2018-05-29T12:03:02.000-04:00
I'd even avoid creating the venv if I could. Still, it's nice to have flake8 run by tox so local test runs automatically do linting.
diff --git a/tox.ini b/tox.ini
@@ -7,6 +7,7 @@ commands = python setup.py test
 [testenv:py36-flake]
 # Pinned so new checks aren't added by surprise:
 deps = flake8>=3.5,<3.6
+skip_install=True
 commands = flake8 sphinx_js
 
 [flake8]
