Using Tox

The quality of code for anomalib maintained by using tools such as black, mypy, and flake8. In order to enforce these, we use Tox. This is also the reason why we don’t have dependencies such as pytest in the requirements.txt file.

What is tox?

tox aims to automate and standardize testing in Python. It is part of a larger vision of easing the packaging, testing and release process of Python software.

It is a generic virtualenv management and test command line tool you can use for:

  • checking that your package installs correctly with different Python versions and interpreters

  • running your tests in each of the environments, configuring your test tool of choice

  • acting as a frontend to Continuous Integration servers, greatly reducing boilerplate and merging CI and shell-based testing. - from the docs

See getting started to dive in and get tox working on your system. If you want to know more about the tox.ini file, check out the brief explanation.

Setting-up and Getting Started

Setting up tox is easy

  1. Create new Conda environment conda create -n toxenv python=3.8

  2. Activate the environment conda activate toxenv

  3. Install tox pip install tox

  4. Run tox It should setup the environments and install the dependencies.

Note

All developers are required to run tox before creating their MR. If you have setup pre-commit hooks then this step can be skipped.

Brief Explanation of tox.ini

Here is a brief explanation of tox.ini for those who are interested. However, for more details, the readers are directed to the official docs.

All tox files start with [tox]

isolated_build = True tells tox to use a virtual environment instead of using the global python.

skip_missing_interpreters = True allows tox to run even if some specified environments are missing.

envlist This defines all the environments that tox should create. Take for example that we want to create an environment to run black formatter. We can name this environment as:

[tox]
envlist =
    black_env

Then to define the commands in this environment all we need to do is start a block with [testenv:black_env] and then define the dependencies and call the commands.

[testenv:black_env]
    deps = black
    commands = black .

For a more elaborate setup, refer to the tox.ini file in this repository.

Useful Tox CheatSheet

  • tox -e envname[,name1,name2] - to run only those environments

  • tox -r [envname..] - to recreate all/specific environments. Handy when the requirements have changed

  • tox -l - to list all environments