diff --git a/test_conflict_set.py b/test_conflict_set.py
index 6f90aea..c18f83b 100644
--- a/test_conflict_set.py
+++ b/test_conflict_set.py
@@ -96,6 +96,7 @@ def test_inner_full_words():
 
 def test_internal_version_zero():
     with DebugConflictSet() as cs:
+        cs.addWrites(0xFFFFFFF0)
         cs.setOldestVersion(0xFFFFFFF0)
         for i in range(24):
             cs.addWrites(0xFFFFFFF1, write(bytes([i])))