Feature request: Tests for backend

[irishrain]

What's the feature 🧐

As discussed in the comments for #305 there are currently no backend tests that actually set up the db, populate it and then test the api. To avoid breaking things accidentally, add tests that verify that the backend is working as expected.

Extra information and references

I started working on this in my fork of the backend - this issue is so you know I'm doing this and avoid duplicate work. I don't have that much free time, so reaching enough coverage for a pull request will take some time. My goal is to have at least tests for a complete cycle of creating a household, creating a user, adding items to the shopping list, adding a recipe, scheduling the recipe, adding the ingredients for the scheduled recipe to the shopping list, and finally clearing the shopping list.

[TomBursch]

Awesome, just be aware that I turned Kitchenowl into a monorepo just now, so you'll need to fork this repo instead and copy your changes over.

[irishrain]

I recently played around with AI agents. They are surprisingly good at creating automated tests, and improving the actual code at the same time (by adding testcases that uncover bugs and then fixing the bugs. In my experiment a lot of validation code was added to make things more robust). Would you be interested in applying this to Kitchenowl? I'm asking because I expect that to produce quite a lot of changes all over the codebase, and it might be hard to review them.