Add flake8 configuration

setup.cfg

@@ -47,6 +47,30 @@ include =
 console_scripts =
 	rsrcfork = rsrcfork.__main__:main
 
+[flake8]
+exclude =
+	.mypy_cache/,
+	build/,
+	dist/,
+	# The following entries would also be added by default by flake8 when not specifying a custom exclude list.
+	# TODO Once flake8 3.8.0 is released, change the name of this configuration setting from exclude to extend-exclude and remove the entries below.
+	.git/,
+	.tox/,
+	__pycache__/,
+
+# The following issues are ignored because they do not match our code style:
+ignore =
+	E226, # missing whitespace around arithmetic operator
+	E261, # at least two spaces before inline comment
+	E501, # line too long
+	W293, # blank line contains whitespace
+	W503, # line break before binary operator
+
+# flake8-tabs configuration
+use-flake8-tabs = true
+blank-lines-indent = always
+indent-tabs-def = 1
+
 [mypy]
 files=rsrcfork/**/*.py
 python_version = 3.6

tox.ini

@@ -1,10 +1,16 @@
 [tox]
 # When adding a new Python version here, please also update the list of Python versions called by the GitHub Actions workflow (.github/workflows/ci.yml).
-envlist = py{36,37,38},mypy
+envlist = py{36,37,38},flake8,mypy
 
 [testenv]
 commands = {envpython} -m unittest discover --start-directory ./tests
 
+[testenv:flake8]
+deps =
+	flake8
+	flake8-tabs
+commands = flake8
+
 [testenv:mypy]
 deps =
 	mypy