Disable the creation of the __pycache__ directory... From pytest.ini / pyproject.toml

Problem Statement

In order to keep project directory structures clean and non-distracting, I’d like to:

1. Prevent the creation of __pycache__ directories when running tests
2. Control this behavior from existing config files (pytest.ini or pyproject.toml)

Use Case

Simple projects that don’t benefit from bytecode caching would benefit from a cleaner directory structure. A solution would consolidate pytest configuration and reduce the need for extra files, eg, .gitignore or a test-runner.sh.

Workarounds

1. Set an environment variable during pytest invokation, eg, PYTHONDONTWRITEBYTECODE=1 pytest (see: #200)
2. Create a post-test cleanup script to delete the cache
3. Ignore the cache directories via .gitignore

Caveats:

• Solutions 1 and 2 require the user to manually configure pytest behavior at invocation or pushes pytest behavior to an extra file (eg. test-runner.sh).
• Solution 3 cleans up the project at the git repository level but requires a .gitignore file and creates cache directories at a local level.

[maxsu]

@The-Compiler I think your argument is analagous to this:

Hi, I have a dog named Pytest, but it makes a mess. Can I train it to make less mess?

Look, I have five dogs, and they all make messes. So there’s no use training Pytest. Let it be a dog!

But I really do just testing in most sessions, and if I deal with one mess at a time, my environment stays clean.

I would like to implement the feature and get it into the standard build or standard plugins. I would really appreciate suggestions that’ll help the PR go through, thanks!

[RonnyPfannschmidt]

a possible consideration could be on whether pytest should support putting pyc files into the pytest cache folder based on a argument

but thats not what this is about

im also -1 on a pytest local option for this based on missed errors/issue in the past when running without bytecode