diff --git a/tests/test_simple_indexer.py b/tests/test_simple_indexer.py
index d8192ab4..4dcabfbf 100644
--- a/tests/test_simple_indexer.py
+++ b/tests/test_simple_indexer.py
@@ -26,7 +26,7 @@ def _test_any(self, cls):
         a = cls()
         self.assertEqual(a.num_chunks, 0)
         a.add(self.key_offset, self.weights)
-        self.assertEqual(a.size, self.num_sample)
+        self.assertEqual(a.num_chunks, self.num_sample)
 
         res1 = a.query(self.query)
         res2 = [(*self.key_offset[q], self.weights[q]) for q in self.query]