The vars-check test was failing because it only included the
runtimeInputs of generators but not the actual generator scripts
themselves. This caused the test to fail when trying to execute
generators that reference local files (like generate.py).
Added allGeneratorScripts to the closureInfo to ensure all generator
scripts and their dependencies are available in the test environment.
This is an improvement of the clanTest nixos vm test module.
The module now has a new option clan.test.fromFlake that allows to specify a flake.nix as the source for the test clan instead of specifying clan.XXX options.
This in turn allows accessing the `flake.nix` inside the test driver allowing to use the clan cli on it
We want each machine not only to be exposed via nixosConfigurations but also as a module.
This allows re-importing the machine in tests and override the architecture for example.
