Add format check with black to tox configuration

Cito · Cito · commit 2255e0269348 · 2018-09-19T16:13:24.000+02:00
diff --git a/tox.ini b/tox.ini
@@ -1,11 +1,17 @@
 [tox]
-envlist = py{36,37}, flake8, mypy
+envlist = py{36,37}, black, flake8, mypy
 
 [travis]
 python =
     3.7: py37
     3.6: py36
 
+[testenv:black]
+basepython = python
+deps = black
+commands  =
+    black graphql tests --check
+
 [testenv:flake8]
 basepython = python
 deps = flake8
