Add flake8 quality checks to tox.ini

tox.ini

@@ -29,6 +29,30 @@ deps =
 commands =
     {posargs:pytest --cov --cov-report=term-missing tests}
 
+[flake8]
+max-line-length = 79
+verbose = 2
+statistics = True
+ignore =
+;   -- flake8 --
+;    E501 line too long
+    E501
+
+per-file-ignores =
+;    F401 imported but unused
+;    E402 module level import not at top of file
+    core/__init__.py: E402, F401
+    core/utils/__init__.py: F401
+    core/plugins/downloaders/configuration.py: F401
+    core/plugins/downloaders/utils.py: F401
+
+[testenv:check]
+deps =
+    flake8
+skip_install = true
+commands =
+    flake8 core tests setup.py
+
 [coverage:run]
 omit =
     libs/*