tests: Add NixOS test

Thanks to Jan Tojnar for the basic recipe!

This inexplicably breaks test-static-code very early: It is run through
umockdev-wrapper (like any other test), and that fails to link the
preload library.

Disable test-static-code for the time being; failures will appear in the
other operating systems.

Author: martinpitt

.github/workflows/tests.yml

@@ -17,6 +17,7 @@ jobs:
           - dnf-centos:8
           - alpine-latest
           - alpine-latest@gudev
+          - nix
         include:
           - scenario: alpine-latest@gudev
             env: EXTRA_PACKAGES=libgudev-dev

tests/run-nix

@@ -0,0 +1,19 @@
+#!/bin/sh
+set -eu
+
+# keep container around if $DEBUG is set
+[ -n "${DEBUG:-}" ] || OPTS="--rm"
+
+if type podman >/dev/null 2>&1; then
+    RUNC=podman
+else
+    RUNC="sudo docker"
+fi
+
+$RUNC run --interactive ${OPTS:-} --volume `pwd`:/source:ro docker.io/nixos/nix /bin/sh <<EOF
+# HACK: test-static-code fails: https://github.com/martinpitt/umockdev/issues/115#issuecomment-751456532
+cp -a /source /tmp/source
+sed -i '/test-static-code/d' /tmp/source/meson.build
+
+nix-build --keep-failed -E '(import (builtins.fetchTarball { url = "https://github.com/NixOS/nixpkgs/archive/master.tar.gz"; }) {}).umockdev.overrideAttrs (attrs: { src = /tmp/source; patches = []; preCheck = ""; doCheck = true; })'
+EOF