add isort and autoformat

setup.cfg

@@ -39,3 +39,14 @@ ignore =
 # Doc8 Configuration
 [doc8]
 max-line-length = 120
+
+[isort]
+line_length = 120
+# https://github.com/timothycrosley/isort#multi-line-output-modes
+multi_line_output = 3
+include_trailing_comma = True
+force_grid_wrap = 0
+combine_as_imports = True
+not_skip = __init__.py
+known_first_party = base64io
+known_third_party =base64io,mock,pytest,setuptools

tox.ini

@@ -129,6 +129,35 @@ deps =
 commands =
     {[testenv:blacken-src]commands} --diff
 
+[testenv:isort-seed]
+basepython = python3
+deps = seed-isort-config
+commands = seed-isort-config
+
+[testenv:isort]
+basepython = python3
+deps = isort
+commands = isort -rc \
+    src \
+    test \
+    doc \
+    setup.py \
+    {posargs}
+
+[testenv:isort-check]
+basepython = python3
+deps = {[testenv:isort]deps}
+commands = {[testenv:isort]commands} -c
+
+[testenv:autoformat]
+basepython = python3
+deps =
+    {[testenv:blacken]deps}
+    {[testenv:isort]deps}
+commands =
+    {[testenv:blacken]commands}
+    {[testenv:isort]commands}
+
 [testenv:pylint]
 basepython = {[testenv:default-python]basepython}
 deps =