smoke test : remove temporary files afterwards

tests/smoke/run.sh

@@ -2,10 +2,12 @@ set -e
 NIXPKGS_ALLOW_UNSUPPORTED_SYSTEM=1 nix-build '<liminix>' -I liminix-config=./configuration.nix --arg device "import <liminix/devices/$DEVICE.nix>" -A outputs.squashfs -o smoke.img $*
 
 TESTS=$(cat <<"EOF"
-
-trap 'echo "command $(eval echo $BASH_COMMAND) failed with exit code $?"; exit $?' ERR
+test -n "${TMPDIR}"
 dest_path=${TMPDIR}/smoke.img-$$
 echo $dest_path
+cleanup(){  test -n ${dest_path} && test -d ${dest_path} && chmod -R +w ${dest_path} && rm -rf ${dest_path};  }
+trap cleanup EXIT
+trap 'echo "command $(eval echo $BASH_COMMAND) failed with exit code $?"; exit $?' ERR
 unsquashfs -q -d $dest_path -excludes smoke.img  /dev
 cd $dest_path;
 db=nix/store/*-s6-rc-db/compiled/