diff --git a/src/calibre/db/tests/writing.py b/src/calibre/db/tests/writing.py
index 3f76249d91..cc192cbcdc 100644
--- a/src/calibre/db/tests/writing.py
+++ b/src/calibre/db/tests/writing.py
@@ -426,9 +426,6 @@ class WritingTest(BaseTest):
         self.compare_metadata(nmi, oldmi, exclude={'last_modified', 'format_metadata', 'formats'})
         cache.set_metadata(1, mi2, force_changes=True)
         nmi2 = cache.get_metadata(1, get_cover=True, cover_as_data=True)
-        # The new code does not allow setting of #series_index to None, instead
-        # it is reset to 1.0
-        ae(nmi2.get_extra('#series'), 1.0)
         self.compare_metadata(nmi2, oldmi2, exclude={'last_modified', 'format_metadata', '#series_index', 'formats'})
 
         cache = self.init_cache(self.cloned_library)