added black for lint check

setup.cfg

@@ -0,0 +1,4 @@
+[flake8]
+# https://github.com/ambv/black#slices
+# https://github.com/ambv/black#line-breaks--binary-operators
+ignore = E203, W503

setup.py

@@ -21,7 +21,7 @@ def open_local(paths, mode='r', encoding='utf8'):
 
 with open_local(['sanic', '__init__.py'], encoding='latin1') as fp:
     try:
-        version = re.findall(r"^__version__ = '([^']+)'\r?$",
+        version = re.findall(r"^__version__ = \"([^']+)\"\r?$",
                              fp.read(), re.M)[0]
     except IndexError:
         raise RuntimeError('Unable to determine version.')

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py35, py36, py37, {py35,py36,py37}-no-ext, flake8, check
+envlist = py35, py36, py37, {py35,py36,py37}-no-ext, lint, check
 
 [testenv]
 usedevelop = True
@@ -21,12 +21,14 @@ commands =
     - coverage combine --append
     coverage report -m
 
-[testenv:flake8]
+[testenv:lint]
 deps =
     flake8
+    black
 
 commands =
     flake8 sanic
+    black --check --verbose sanic
 
 [testenv:check]
 deps =