Run tests with a private XDG_RUNTIME_DIR

Otherwise, service activation will start a new xdg-document-portal
(because we're using a private DBUS_SESSION_BUS_ADDRESS), but because
XDG_RUNTIME_DIR is shared with the real system, it won't be able to
mount its filesystem.

We need to unmount the document portal before removing the private
XDG_RUNTIME_DIR.

Signed-off-by: Simon McVittie <smcv@debian.org>

tests/libtest.sh

@@ -70,11 +70,13 @@ fi
 # We need this to be in /var/tmp because /tmp has no xattr support
 TEST_DATA_DIR=`mktemp -d /var/tmp/test-flatpak-XXXXXX`
 mkdir -p ${TEST_DATA_DIR}/home
+mkdir -p ${TEST_DATA_DIR}/runtime
 mkdir -p ${TEST_DATA_DIR}/system
 export FLATPAK_SYSTEM_DIR=${TEST_DATA_DIR}/system
 export FLATPAK_SYSTEM_HELPER_ON_SESSION=1
 
 export XDG_DATA_HOME=${TEST_DATA_DIR}/home/share
+export XDG_RUNTIME_DIR=${TEST_DATA_DIR}/runtime
 
 export USERDIR=${TEST_DATA_DIR}/home/share/flatpak
 export SYSTEMDIR=${TEST_DATA_DIR}/system
@@ -220,4 +222,9 @@ skip_without_bwrap () {
 sed s#@testdir@#${test_builddir}# ${test_srcdir}/session.conf.in > session.conf
 eval `dbus-launch --config-file=session.conf --sh-syntax`
 
-trap "rm -rf $TEST_DATA_DIR; /bin/kill $DBUS_SESSION_BUS_PID" EXIT
+cleanup () {
+    /bin/kill $DBUS_SESSION_BUS_PID
+    fusermount -u $XDG_RUNTIME_DIR/doc || :
+    rm -rf $TEST_DATA_DIR
+}
+trap cleanup EXIT