Integrate the Black code formatting tool

.travis.yml

@@ -4,6 +4,7 @@ dist: xenial
 sudo: true
 before_install:
   - pip install codecov
+  - pip install black
 install:
   - pip install -e .
 script:

README.md

@@ -2,6 +2,7 @@
 
 [![Build Status](https://travis-ci.com/correl/typesafe-monads.svg?branch=master)](https://travis-ci.com/correl/typesafe-monads)
 [![codecov](https://codecov.io/gh/correl/typesafe-monads/branch/master/graph/badge.svg)](https://codecov.io/gh/correl/typesafe-monads)
+[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/ambv/black)
 
 This is an experiment in building monads in Python supported by strict
 type annotations. The goal is to be able to compose monads with the

pyproject.toml

@@ -0,0 +1,13 @@
+[tool.black]
+line-length = 88
+py36 = true
+include = '\.pyi?$'
+exclude = '''
+/(
+    \.eggs
+  | \.git
+  | \.mypy_cache
+  | build
+  | dist
+)/
+'''

setup.cfg

@@ -2,4 +2,4 @@
 test=pytest
 
 [tool:pytest]
-addopts = --mypy --cov monads --cov-report xml:reports/coverage.xml
+addopts = --black --mypy --cov monads --cov-report xml:reports/coverage.xml

setup.py

@@ -17,7 +17,14 @@ setup(
     package_data={"monads": ["py.typed"]},
     include_package_data=True,
     setup_requires=["pytest-runner"],
-    tests_require=["pytest", "mypy", "pytest-cov", "pytest-mypy"],
+    tests_require=[
+        "pytest",
+        "black",
+        "mypy",
+        "pytest-cov",
+        "pytest-black",
+        "pytest-mypy",
+    ],
     classifiers=[
         "Development Status :: 2 - Pre-Alpha",
         "Intended Audience :: Developers",