Add black formatting

.pre-commit-config.yaml

@@ -9,6 +9,7 @@ repos:
         files: "^connexion/"
         additional_dependencies:
           - flake8-rst-docstrings==0.2.3
+
   - repo: https://github.com/PyCQA/isort
     rev: 5.10.1
     hooks:
@@ -24,3 +25,19 @@ repos:
         name: isort tests
         files: "^tests/"
         args: ["--project", "conftest", "--thirdparty", "connexion", "--check-only", "--diff"]
+
+  - repo: https://github.com/psf/black
+    rev: 22.3.0
+    hooks:
+      - id: black
+        name: black
+        files: "^connexion/"
+        args: ["connexion"]
+      - id: black
+        name: black examples
+        files: "^examples/"
+        args: ["examples"]
+      - id: black
+        name: black tests
+        files: "^tests/"
+        args: ["tests"]

README.rst

@@ -583,8 +583,8 @@ Contributing to Connexion/TODOs
 We welcome your ideas, issues, and pull requests. Just follow the
 usual/standard GitHub practices.
 
-For easy development, please install connexion in editable mode with the :code:`tests` extra, and
-install the pre-commit hooks.
+For easy development, install connexion in editable mode with the :code:`tests` extra, and
+install the pre-commit hooks to automatically run black formatting and static analysis checks.
 
 .. code-block:: bash
 

tox.ini

@@ -1,7 +1,13 @@
 [flake8]
-max-line-length=170
 exclude=connexion/__init__.py
 rst-roles=class
+# https://black.readthedocs.io/en/stable/guides/using_black_with_other_tools.html#flake8
+# Longest docstring in current code base
+max-line-length=137
+extend-ignore=E203
+
+[isort]
+profile = black
 
 [tox]
 envlist =