Well that is a mess. I don't like breaking derivation compatibility,
but I like non-deterministic evaluation much less.
We can break compat if we own up to it, which this does.
Fixes: https://git.lix.systems/lix-project/lix/issues/750
Change-Id: Ic9e2407393f1d42c2be604f80b4aa11bc872bc23
I think it is bad for these reasons when `tests/` contains a mix of
functional and integration tests
- Concepts is harder to understand, the documentation makes a good
unit vs functional vs integration distinction, but when the
integration tests are just two subdirs within `tests/` this is not
clear.
- Source filtering in the `flake.nix` is more complex. We need to
filter out some of the dirs from `tests/`, rather than simply pick
the dirs we want and take all of them. This is a good sign the
structure of what we are trying to do is not matching the structure
of the files.
With this change we have a clean:
```shell-session
$ git show 'HEAD:tests'
tree HEAD:tests
functional/
installer/
nixos/
```
(cherry picked from commit 68c81c737571794f7246db53fb4774e94fcf4b7e)