Test factories

This repository's purpose is to show examples on how to define and use test factories using the library factory-boy.

Factory is a generic object-oriented software pattern that uses a class or a function to build objects of a certain kind, but not using the constructor.

In particular, this repository uses the more specific pattern Object Mother, but for consistency with the library and habit, it uses Factory as the concept in most examples.

For more info on Object Mother pattern, you can start with Martin's Fowler article:

https://martinfowler.com/bliki/ObjectMother.html

To show the use of factoryboy we will use pytest and sqlalchemy, to exemplify advanced usage, closest to the real world. This example can be easily translated to other framework and tools, namely Django and its ORM, or Mongo.

Additionally, we will be using faker, another great tool, to generate random data.

For more modern libraries, while factory-boy is still a good option, newer libraries have popped out like polyfactory. The examples shown in this repository should be applicable with some effort into polyfactory or any other library in Python or in any other languages

Other interesting things about this repo

This repo uses pre-commit and several tools to keep the repo style consistent and in shape. You can take a look and reuse them.

• doit: dodo.py
• make: Makefile
• pre-commit: .pre-commit-config.yaml
  • uses black, isort, pylint, interrogate

Configuration is either in setup.cfg or pyproject.toml

How to install

sudo apt install libpq-dev python3-dev
pipenv install --dev

For other dependency systems use requirements.txt

This project has been developed and tested in python 3.10 but it should be compatible with 3.8+.

How to launch tests

docker compose up -d
pipenv shell
pytest

Acknowledgments

I want to thank my colleagues and former colleagues at CitNOW which have contributed to set up and evolve our testing and tooling skills, these examples are partially based on our work together.