diff --git a/Lib/test/string_tests.py b/Lib/test/string_tests.py
index ea49e38..4964248 100644
--- a/Lib/test/string_tests.py
+++ b/Lib/test/string_tests.py
@@ -172,6 +172,9 @@
         self.checkequal(-1, '', 'find', 'xx', 1, 1)
         self.checkequal(-1, '', 'find', 'xx', sys.maxsize, 0)
 
+        # issue 7458
+        self.checkequal(-1, 'ab', 'find', 'xxx', sys.maxsize + 1, 0)
+
         # For a variety of combinations,
         #    verify that str.find() matches __contains__
         #    and that the found substring is really at that location
@@ -240,6 +243,9 @@
                 if loc != -1:
                     self.assertEqual(i[loc:loc+len(j)], j)
 
+        # issue 7458
+        self.checkequal(-1, 'ab', 'rfind', 'xxx', sys.maxsize + 1, 0)
+
     def test_index(self):
         self.checkequal(0, 'abcdefghiabc', 'index', '')
         self.checkequal(3, 'abcdefghiabc', 'index', 'def')