Long term passthru.tests portability between nixpkgs <-> flakes?

abathur · October 12, 2022, 7:23pm

I’m finally trying out flakes in the context of some old projects.

I might want to add them to nixpkgs some day, so it seems ideal to be able to create tests as passthru.tests derivations and also run them with nix flake check.

I asked around on Matrix for existing patterns and got this example:

github.com

lilyinstarlight/foosteros/blob/bcc6fa06cfc170556edc57e08b1770a0b2557d0b/tests/pkgs.nix

{ pkgs, self, ... }:

with pkgs;

lib.listToAttrs (lib.flatten (
  map (drv: if drv ? tests
    then lib.mapAttrsToList (name: value: { name = "pkg-test-" + (if drv ? pname then drv.pname else drv.name) + "-" + name; inherit value; }) drv.tests
    else []
  )
    (lib.unique (lib.filter (drv: !drv.meta.unsupported && !drv.meta.unfree && (drv.meta ? dependsUnfree -> !drv.meta.dependsUnfree)) (lib.collect
      (drv: lib.isDerivation drv)
      self.legacyPackages.${pkgs.stdenv.hostPlatform.system}
    )))
))

Since I’ve imagined flakes helping smooth out the work necessary to pull a package into nixpkgs or push it back out into a secondary package collection, this feels like a conspicuous amount of friction. Am I overlooking something?