Add pre-commit config and apply changes (#54)

- Add .pre-commit-config.yaml with initial config.
- Add python black pre-commit config
- Apply pre-commit code changes
- Add information to CONTRIBUTING.md
- Add pre-commit to build requirements
- Run pre-commit during travis CI build
- Use a travis build matrix to control when pre-commit runs
  in the CI process. Use explicit include to only run
  pre-commit on Python 3.9.

Author: jongracecox

.pre-commit-config.yaml

@@ -0,0 +1,16 @@
+repos:
+- repo: https://github.com/pre-commit/pre-commit-hooks
+  rev: v4.3.0
+  hooks:
+  - id: trailing-whitespace
+  - id: end-of-file-fixer
+  - id: check-case-conflict
+  - id: check-yaml
+  - id: requirements-txt-fixer
+  - id: mixed-line-ending
+  - id: no-commit-to-branch
+    args: [--branch, master]
+- repo: https://github.com/psf/black
+  rev: 22.6.0
+  hooks:
+    - id: black

.travis.yml

@@ -1,15 +1,27 @@
 dist: xenial
 language: python
-python:
-- '3.4'
-- '3.5'
-- '3.6'
-- '3.7'
-- '3.8'
-- '3.9'
+jobs:
+  include:
+    - python: '3.4'
+      env: RUN_PRE_COMMIT=0
+    - python: '3.5'
+      env: RUN_PRE_COMMIT=0
+    - python: '3.6'
+      env: RUN_PRE_COMMIT=0
+    - python: '3.7'
+      env: RUN_PRE_COMMIT=0
+    - python: '3.8'
+      env: RUN_PRE_COMMIT=0
+    - python: '3.9'
+      env: RUN_PRE_COMMIT=1
 install:
 - pip install -U setuptools pip -r build-requirements.txt
 script:
+- if [[ $RUN_PRE_COMMIT = 1 ]]; then
+    pip install -U pre-commit==2.12.1 &&
+    pre-commit install &&
+    pre-commit run --all;
+  fi
 - pytest --doctest-modules --cov=anybadge --cov-report html:htmlcov anybadge tests
 before_deploy:
 - sed -i "s/^version = .*/version = __version__ = \"$TRAVIS_TAG\"/" anybadge.py
@@ -23,4 +35,4 @@ deploy:
   on:
     tags: true
     all_branches: true
-    python: '3.9'
+    python: '3.9'

CONTRIBUTING.md

@@ -8,7 +8,7 @@ I love your input! I want to make contributing to this project as easy and trans
 - Becoming a maintainer
 
 ## I use [Github Flow](https://docs.github.com/en/get-started/quickstart/github-flow), so all code changes happen through pull requests
-Pull requests are the best way to propose changes to the codebase (I use 
+Pull requests are the best way to propose changes to the codebase (I use
 [Github Flow](https://docs.github.com/en/get-started/quickstart/github-flow)). I actively welcome your pull requests:
 
 1. Fork the repo and create your branch from `master`
@@ -20,7 +20,7 @@ Pull requests are the best way to propose changes to the codebase (I use
 
 ## Any contributions you make will be under the MIT Software License
 When you submit code changes, your submissions are understood to be under the same
-[MIT License](http://choosealicense.com/licenses/mit/) that covers the project. Feel free to contact the maintainers 
+[MIT License](http://choosealicense.com/licenses/mit/) that covers the project. Feel free to contact the maintainers
 if that's a concern.
 
 ## Report bugs using Github's [issues](https://github.com/jongracecox/anybadge/issues)
@@ -48,6 +48,42 @@ By contributing, you agree that your contributions will be licensed under its MI
 
 # Technical stuff
 
+## Pre-commit
+This projects makes use of [pre-commit](https://pre-commit.com) to add some safety checks and create consistency
+in the project code. When committing changes to this project, please first [install pre-commit](https://pre-commit.com/#install),
+then activate it for this project:
+
+```bash
+pip install pre-commit
+pre-commit install
+```
+
+After installing pre-commit to your project (with `pre-commit install`), committing to the project will trigger a series
+of checks, and fixers. This process may reject your commit or make changes to your code to bring it into line with the
+project standards. For example, [Python black](https://github.com/psf/black) will be used to reformat any code. When
+changes are made by these pre-commit hooks you will need to re-add and commit those changes in order for pre-commit to
+pass.
+
+Here is some example output from pre-commit:
+
+```
+trim trailing whitespace.................................................Failed
+- hook id: trailing-whitespace
+- exit code: 1
+- files were modified by this hook
+
+Fixing tests/test_anybadge.py
+
+fix end of files.........................................................Failed
+- hook id: end-of-file-fixer
+- exit code: 1
+- files were modified by this hook
+
+Fixing examples/color_teal.svg
+```
+
+This shows that two files were updated by hooks, and need to be re-added (with `git add`) before trying to commit again.
+
 ## Documentation
 The `README.md` file contains a table showing example badges for the different built-in colors. If you modify the
 appearance of badges, or the available colors please update the table using the following code:

TODO.md

@@ -7,4 +7,4 @@
 * [ ] Add CI test for Docker image
 * [ ] Add CI to push server to Docker hub
 * [ ] Support common badge server URL structure
-* [ ] Documentation for all docker bits
+* [ ] Documentation for all docker bits

anybadge/__init__.py

@@ -5,7 +5,7 @@
 
 # Package information
 version = __version__ = "0.0.0"
-__version_info__ = tuple(re.split('[.-]', __version__))
+__version_info__ = tuple(re.split("[.-]", __version__))
 __title__ = "anybadge"
 __summary__ = "A simple, flexible badge generator."
 __uri__ = "https://github.com/jongracecox/anybadge"