makeImpureTest: init function for hardware tests

/* Create tests that run in the nix sandbox with additional access to selected host paths

  This is for example useful for testing hardware where a tests needs access to

  /sys and optionally more.

  The following example shows a test that accesses the GPU:

  Example:

    makeImpureTest {

      name = "opencl";

      testedPackage = "mypackage"; # Or testPath = "mypackage.impureTests.opencl.testDerivation"

      sandboxPaths = [ "/sys" "/dev/dri" ]; # Defaults to ["/sys"]

      prepareRunCommands = ""; # (Optional) Setup for the runScript

      nixFlags = []; # (Optional) nix-build options for the runScript

      testScript = "...";

    }

  Save as `test.nix` next to a package and reference it from the package:

    passthru.impureTests = { opencl = callPackage ./test.nix {}; };

  `makeImpureTest` will return here a script that contains the actual nix-build command including all necessary sandbox flags.

  It can be executed like this:

    $(nix-build -A mypackage.impureTests)

  Rerun an already cached test:

    $(nix-build -A mypackage.impureTests) --check

*/

{ lib

, stdenv

, writeShellScript

, name

, testedPackage ? null

, testPath ? "${testedPackage}.impureTests.${name}.testDerivation"

, sandboxPaths ? [ "/sys" ]

, prepareRunCommands ? ""

, nixFlags ? [ ]

, testScript

, ...

} @ args:

let

  sandboxPathsTests = builtins.map (path: "[[ ! -e '${path}' ]]") sandboxPaths;

  sandboxPathsTest = lib.concatStringsSep " || " sandboxPathsTests;

  sandboxPathsList = lib.concatStringsSep " " sandboxPaths;

  testDerivation = stdenv.mkDerivation (lib.recursiveUpdate

    {

      name = "test-run-${name}";

      requiredSystemFeatures = [ "nixos-test" ];

      buildCommand = ''

        mkdir -p $out

        if ${sandboxPathsTest}; then

          echo 'Run this test as *root* with `--option extra-sandbox-paths '"'${sandboxPathsList}'"'`'

          exit 1

        fi

        # Run test

        ${testScript}

      '';

      passthru.runScript = runScript;

    }

    (builtins.removeAttrs args [

      "lib"

      "stdenv"

      "writeShellScript"

      "name"

      "testedPackage"

      "testPath"

      "sandboxPaths"

      "prepareRunCommands"

      "nixFlags"

      "testScript"

    ])

  );

  runScript = writeShellScript "run-script-${name}" ''

    set -euo pipefail

    ${prepareRunCommands}

    sudo nix-build --option extra-sandbox-paths '${sandboxPathsList}' ${lib.escapeShellArgs nixFlags} -A ${testPath} "$@"

  '';

in

# The main output is the run script, inject the derivation for the actual test

runScript.overrideAttrs (old: {

  passthru = { inherit testDerivation; };

})

  makeAutostartItem = callPackage ../build-support/make-startupitem { };

  makeImpureTest = callPackage ../build-support/make-impure-test.nix;

  makeInitrd = callPackage ../build-support/kernel/make-initrd.nix; # Args intentionally left out

  makeInitrdNG = callPackage ../build-support/kernel/make-initrd-ng.nix;