rename needs erasing

Author: Carreau

zarr/tests/test_storage.py

@@ -351,7 +351,7 @@ def test_hierarchy(self):
             assert [] == store.listdir('c/e/f')
 
         # test rename (optional)
-        if hasattr(store, 'rename'):
+        if store.is_erasable():
             try:
                 store.rename("c/e", "c/e2")
                 assert "c/d" in store