Cannot run nix-unit in derivation build #183
Description
Problem
I want to run unit tests in CI, which is why I tried to wrap the invocation of nix-unit in runCommand. This doesn't work though, presumably because nix-unit tries to initialise its own Nix shenanigans but fails.
Reproducer
default.nix
{ sources ? import ./npins
, system ? builtins.currentSystem
, pkgs ? import sources.nixpkgs {
inherit system;
config = { };
overlays = [ ];
}
}:
rec {
run-tests = pkgs.writeShellApplication {
name = "run-tests";
text = with pkgs; with lib; ''
${getExe nix-unit} ${toString ./tests.nix} "$@"
'';
};
shell =
pkgs.mkShellNoCC {
packages = [
pkgs.npins
run-tests
];
};
tests = with pkgs; with lib; runCommand "run-tests" { } ''
touch $out
${getExe nix-unit} ${./tests.nix} "$@"
'';
}tests.nix
{
testTest = {
expr = 1 + 1;
expected = 2;
};
}$ npins init
$ echo '(import ./. { }).shell' > shell.nix
$ echo use_nix >> .envrc
$ direnv allow
$ run-tests
warning: unknown setting 'allowed-users'
warning: unknown setting 'trusted-users'
warning: `--gc-roots-dir' not specified
✅ testTest
🎉 1/1 successful
$ nix-build -A tests
this derivation will be built:
/nix/store/ai9r71fk66a29f6h23aqqqxl516w59yq-run-tests.drv
building '/nix/store/ai9r71fk66a29f6h23aqqqxl516w59yq-run-tests.drv'...
warning: `--gc-roots-dir' not specified
error: creating directory '/nix/var/nix/profiles': Permission denied
error: builder for '/nix/store/ai9r71fk66a29f6h23aqqqxl516w59yq-run-tests.drv' failed with exit code 1;
last 2 log lines:
> warning: `--gc-roots-dir' not specified
> error: creating directory '/nix/var/nix/profiles': Permission denied
For full logs, run 'nix log /nix/store/ai9r71fk66a29f6h23aqqqxl516w59yq-run-tests.drv'.Ruminations
Maybe this can be fixed somewhat easily by setting the relevant Nix configuration options on the nix-unit side such that it doesn't even try to get outside of the derivation sandbox, e.g. by pointing profiles to /tmp.