qa: Wait for purge to complete in test_volume_info_pending_subvol_deletions

Fixes: https://tracker.ceph.com/issues/62278
Signed-off-by: Kotresh HR <[email protected]>

Author: kotreshhr

qa/tasks/cephfs/test_volumes.py

@@ -668,14 +668,16 @@ def test_volume_info_pending_subvol_deletions(self):
         subvolname = self._generate_random_subvolume_name()
         # create subvolume
         self._fs_cmd("subvolume", "create", self.volname, subvolname, "--mode=777")
-        # create 3K files of 0.1MB
-        self._do_subvolume_io(subvolname, number_of_files=3000, file_size=0.1)
+        # create 3K zero byte files
+        self._do_subvolume_io(subvolname, number_of_files=3000, file_size=0)
         # Delete the subvolume
         self._fs_cmd("subvolume", "rm", self.volname, subvolname)
         # get volume metadata
         vol_info = json.loads(self._get_volume_info(self.volname))
         self.assertNotEqual(vol_info['pending_subvolume_deletions'], 0,
                             "pending_subvolume_deletions should be 1")
+        # verify trash dir is clean
+        self._wait_for_trash_empty()
 
     def test_volume_info_without_subvolumegroup(self):
         """