tests: Skip MemoryMonitor test if GObject-Introspection is too old

Distributions will likely want to update GLib before
GObject-Introspection, to avoid circular dependencies.

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

gio/tests/memory-monitor-portal.py.in

@@ -40,6 +40,12 @@ class TestLowMemoryMonitorPortal(dbusmock.DBusTestCase):
         klass.start_session_bus()
 
     def setUp(self):
+        try:
+            Gio.MemoryMonitor
+        except AttributeError:
+            raise unittest.SkipTest('Low memory monitor not in '
+                                    'introspection data. Requires '
+                                    'GObject-Introspection ≥ 1.63.2')
         try:
             (self.p_mock, self.obj_lmm) = self.spawn_server_template(
                 'low_memory_monitor', {}, stdout=subprocess.PIPE)