@@ -681,6 +681,7 @@ t_dropWord16 m t = dropWord16 m t `T.isSuffixOf` t
681681t_takeWord16 m t = takeWord16 m t `T.isPrefixOf` t
682682t_take_drop_16 m t = T.append (takeWord16 n t) (dropWord16 n t) == t
683683 where n = small m
684+t_use_from t = monadicIO $ assert . (==t) =<< run (useAsPtr t fromPtr)
684685
685686-- Regression tests.
686687s_filter_eq s = S.filter p t == S.streamList (filter p s)
@@ -1087,6 +1088,7 @@ tests = [
10871088 testGroup "lowlevel" [
10881089 testProperty "t_dropWord16" t_dropWord16,
10891090 testProperty "t_takeWord16" t_takeWord16,
1090− testProperty "t_take_drop_16" t_take_drop_16
1091+ testProperty "t_take_drop_16" t_take_drop_16,
1092+ testProperty "t_use_from" t_use_from
10911093 ]
10921094 ]