Run flake8 with tests. Add flake8 config to ignore common exclusions. Add comments to testing and docs extras to aid with merges.

.flake8

@@ -0,0 +1,2 @@
+[flake8]
+ignore = W191,W503

pytest.ini

@@ -1,4 +1,4 @@
 [pytest]
 norecursedirs=dist build .tox .eggs
-addopts=--doctest-modules
+addopts=--doctest-modules --flake8
 doctest_optionflags=ALLOW_UNICODE ELLIPSIS

setup.py

@@ -36,14 +36,21 @@ params = dict(
 	],
 	extras_require={
 		'testing': [
+			# upstream
 			'pytest>=2.8',
 			'pytest-sugar>=0.9.1',
 			'collective.checkdocs',
+			'pytest-flake8',
+
+			# local
 		],
 		'docs': [
+			# upstream
 			'sphinx',
 			'jaraco.packaging>=3.2',
 			'rst.linker>=1.9',
+
+			# local
 		],
 	},
 	setup_requires=[