1. Python 3
2. Make

You will need two additional dependencies for this style:

1. pyenv
2. pyenv-virtualenv

Once the above dependencies are installed, do the following:

1. Install an isolated environment for your preferred Python version.

export python_version=<YOUR-PREFERRED-PYTHON-VERSION>
pyenv install $python_version

NOTE: For more available versions, run pyenv install --list

2. Create a virtualenv for this project

pyenv virtualenv $python_version changeme

3. Add a .python-version file to this project dir

cat >.python-version<<EOF
changeme
$python_version
EOF

Your newly created virtualenv should now be automatically activated if your prompt changed to the following:

(changeme) ubuntu@dev...

or, should you happen to be using dotfiles.relaxdiego.com, if it changed to the following

... via 🐍 <YOUR-PREFERRED-PYTHON-VERSION> (changeme)

Notice the things in parentheses that corresponds to the virtualenv you created in the previous step. This is thanks to the coordination of pyenv-virtualenv and the .python-version file in the rootdir of this project.

If you cd .. or cd anywhere else outside your project directory, the virtualenv will automatically be deactivated. When you cd back into the project dir, the virtualenv will automatically be activated.

If you'd rather manage your virtualenv manually, this section is for you. Create your virtual environment:

python3 -m venv ./venv

Activate it in every shell session where you intend to run make or the unit tests

source ./venv/bin/activate

Install all development and runtime dependencies.

WARNING: Make sure you are using a virtualenv before running this command. Since it uses pip-sync to install dependencies, it will remove any package that is not listed in either requirements-dev.in or setup.py. If you followed the steps in any of the Prepare Your Development Environment sections above, then you should be in good shape.

make dependencies

1. Add it to requirements-dev.in and then run make:

echo "foo" >> requirements-dev.in
make dependencies

This will create requirements-dev.txt and then install all dependencies

2. Commit requirements-dev.in and requirements-dev.txt. Both files should now be updated and the foo package installed in your local machine. Make sure to commit both files to the repo to let your teammates know of the new dependency.

git add requirements-dev.*
git commit -m "Add foo to requirements-dev.txt"
git push origin

1. Add it to runtime_requirements list in setup.py and then run:

make dependencies

This will create requirements.txt and then install all dependencies

2. Commit setup.py and ignore requirements.txt. We ignore the latter since this is a library project which may be used with different versions of its dependencues at development and run time.

git add setup.py
git commit -m "Add bar to requirements"
git push origin

After any change in the library, you want to ensure that all unit tests pass before building it. This can be easily done by running:

make test build

To view the coverage report, run the tests first and then run:

make coverage-server

This will run a simple web server on port 5000 that will serve the files in the auto-generated htmlcov/ directory. You may leave this server running in a separate session as you run the tests so that you can just switch back to the browser and hit refresh to see the changes to your coverage down to the line of code.

Run make help or check out the contents of Makefile.

More often than not you want to be able to support more than one version of Python. This is where tox comes in. Just run the following to get test results for all Python versions listed in tox.ini's envlist config option

tox