add rudimentary test harness, turn example-configuration into a test

make-image.nix

@@ -1,14 +1,14 @@
 pkgs: config:
 let
-  inherit (pkgs) buildPlatform callPackage runCommandNoCC closureInfo stdenv writeText s6-rc;
+  inherit (pkgs) buildPlatform callPackage stdenvNoCC closureInfo stdenv writeText s6-rc;
 
   # we need to generate s6 db,  by generating closure of all
   # config.services and calling s6-rc-compile on them
   allServices = closureInfo {
     rootPaths = builtins.attrValues config.services;
   };
-  s6db = stdenv.mkDerivation {
-    name = "make-s6-db";
+  s6db = stdenvNoCC.mkDerivation  {
+    name = "s6-rc-db";
     nativeBuildInputs = [pkgs.buildPackages.s6-rc];
     builder = writeText "find-s6-services" ''
     source $stdenv/setup

run-tests.sh

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+
+export TMPDIR=${TMPDIR-/tmp}
+for i in tests/*/run.sh; do
+    echo $i
+    $i
+done

tests/smoke/run.sh

@@ -0,0 +1,22 @@
+set -e
+NIXPKGS_ALLOW_UNSUPPORTED_SYSTEM=1 nix-build  -I liminix-config=./tests/smoke/configuration.nix -o smoke.img
+
+TESTS=$(cat <<"EOF"
+
+trap 'echo "command $(eval echo $BASH_COMMAND) failed with exit code $?"; exit $?' ERR
+dest_path=${TMPDIR}/smoke.img-$$
+echo $dest_path
+unsquashfs -q -d $dest_path smoke.img
+cd $dest_path;
+db=*-s6-rc-db/compiled/
+test -d $db
+chmod -R +w $db
+# check we have closure of config.services (lo.link.service exists only
+# as a dependency)
+test "$(s6-rc-db -c $db type lo.link.service)" = "oneshot"
+echo OK
+EOF
+     )
+
+
+nix-shell -p s6-rc -p squashfsTools --run "$TESTS" || exit 1