Adding a test case:
Create a directory in the tests directory with a flake.nix and flake.lock.
Do not have any external dependencies or flake inputs.
Construct your test and then capture the output with add-test.sh:
./add-test.sh directoryName
like:
./add-test.sh devShellWithDevShellsAndPackages
This will create a directoryName.json and directoryName.check-err file.
If the test is not specific to the error output handling, delete the check-err file.