diff --git a/testsuite/MDAnalysisTests/coordinates/test_xdr.py b/testsuite/MDAnalysisTests/coordinates/test_xdr.py
index 1f267efc8d..b8eb68364e 100644
--- a/testsuite/MDAnalysisTests/coordinates/test_xdr.py
+++ b/testsuite/MDAnalysisTests/coordinates/test_xdr.py
@@ -1028,7 +1028,7 @@ def test_persistent_offsets_readonly(self, tmpdir):
 
     def test_offset_lock_created(self):
         assert os.path.exists(
-            XDR.offsets_filename(self.filename)
+            XDR.offsets_filename(self.filename, ending="lock")
         )