diff --git a/string/test/predicate_test.cpp b/string/test/predicate_test.cpp
index 285032e..f200a0e 100644
--- a/string/test/predicate_test.cpp
+++ b/string/test/predicate_test.cpp
@@ -58,12 +58,11 @@ void predicate_test()
 
     BOOST_CHECK( lexicographical_compare("abc", "abd") );
     BOOST_CHECK( !lexicographical_compare("abc", "abc") );
-    BOOST_CHECK( lexicographical_compare("abc", "abd", is_not_greater()) );
-    BOOST_CHECK( lexicographical_compare("abc", "abc", is_not_greater()) );
+    BOOST_CHECK( lexicographical_compare("abc", "abd", is_less()) );
 
     BOOST_CHECK( !ilexicographical_compare("aBD", "AbC") );
     BOOST_CHECK( ilexicographical_compare("aBc", "AbD") );
-    BOOST_CHECK( lexicographical_compare("abC", "aBc", is_not_igreater()) );
+    BOOST_CHECK( lexicographical_compare("abC", "aBd", is_iless()) );
 
     // multi-type comparison test
     BOOST_CHECK( starts_with( vec1, string("123") ) );