General steps while developing cli tools using python3 (following proper TT Test Driven Development)

python3-cli-development-steps

Create project folder
mkdir -p code/fileops

Initialize virtualenv
cd code/fileops
pipenv -python 3.9
pipenv shell
cat Pipefile
git init
git status

Write readme file

Create Makefile
--------------------------------------
.PHONY: default install test

default: test

install:
	pipenv install --dev --skip-lock

test:
	PYTHONPATH=./src pytest
--------------------------------------

Create src code and test folder
mkdir -p src/fileops tests
touch src/fileops/__init__.py tests/.keep

Add .gitignore for python
https://github.com/github/gitignore/blob/master/Python.gitignore
https://raw.githubusercontent.com/github/gitignore/master/Python.gitignore
Commit it: git commit -m "Initial Commit"

Start writing tests (for parser)
tests -> in tests/test_cli.py
install pytest as dev package we need it (pipenv install --dev pytest)
Also install pytest-mock incase you're using mocker in pytest
Run test using: make
Follow RED -> Green -> Refactor concept after adding each test (following the TDD test driven development)
Install flake8 and black for liniting and formatting python code (pipenv install --dev flake8 black)
Change makefile to include linting
-----------------------------
lint:
	black .
	flake8

lint-check:
	flake8
	black --check --diff .
-----------------------------

Might need to add .flake8 and pyproject.toml file
https://github.com/aquasecurity/kube-hunter/blob/master/.flake8

Write tests files and python code in src folder.

Write setup.py file with metadata info.
---------------------------------------------
from setuptools import setup, find_packages

with open('README.md', encoding='UTF-8') as f:
    readme = f.read()

setup(
    name='fileops',
    version='0.1.0',
    description='Utility to print content of specific line number from a given file.',
    long_description=readme,
    author='Milind',
    author_email='[email protected]',
    packages=find_packages('src'),
    package_dir={'': 'src'},
    install_requires=[],
    entry_points={
        'console_scripts': [
            'fileops=fileops.cli:main',
        ],
    }
)
---------------------------------------------
Install the developed package using: pipenv install -e .
test the package: 

Uninstall package pipenv uninstall package-name
Edit/fix the code and reinstall the package and test it. Repeat.

Add setup.cfg file
--------
[bdist_wheel]
python-tag = py36
--------
Build a wheel distribution
python setup.py bdist_wheel
This will generate wheel file inside dist folder (dist/fileops-0.1.0-py36-none-any.whl)
Use this file with pip install to install our developed package.
Note the python-tag in setup.cfg says the min. version of python on which it will work.