PEP 466: backport hashlib algorithm constants (closes #21307)
diff --git a/Lib/test/test_hashlib.py b/Lib/test/test_hashlib.py
index 3fc172f..76be461 100644
--- a/Lib/test/test_hashlib.py
+++ b/Lib/test/test_hashlib.py
@@ -109,6 +109,15 @@
             tuple([_algo for _algo in self.supported_hash_names if
                                                 _algo.islower()]))
 
+    def test_algorithms_guaranteed(self):
+        self.assertEqual(hashlib.algorithms_guaranteed,
+            set(_algo for _algo in self.supported_hash_names
+                  if _algo.islower()))
+
+    def test_algorithms_available(self):
+        self.assertTrue(set(hashlib.algorithms_guaranteed).
+                            issubset(hashlib.algorithms_available))
+
     def test_unknown_hash(self):
         self.assertRaises(ValueError, hashlib.new, 'spam spam spam spam spam')
         self.assertRaises(TypeError, hashlib.new, 1)