diff --git Lib/test/test_math.py Lib/test/test_math.py
index 525ee09..8fa45c8 100644
--- Lib/test/test_math.py
+++ Lib/test/test_math.py
@@ -365,18 +365,18 @@ class MathTests(unittest.TestCase):
         self.ftest('fabs(1)', math.fabs(1), 1)
 
     def testFactorial(self):
-        def fact(n):
-            result = 1
-            for i in range(1, int(n)+1):
-                result *= i
-            return result
-        values = list(range(10)) + [50, 100, 500]
-        random.shuffle(values)
-        for x in range(10):
-            for cast in (int, float):
-                self.assertEqual(math.factorial(cast(x)), fact(x), (x, fact(x), math.factorial(x)))
+        self.assertEqual(math.factorial(0), 1)
+        self.assertEqual(math.factorial(0.0), 1)
+        total = 1
+        for i in range(1, 1000):
+            total *= i
+            self.assertEqual(math.factorial(i), total)
+            self.assertEqual(math.factorial(float(i)), total)
         self.assertRaises(ValueError, math.factorial, -1)
+        self.assertRaises(ValueError, math.factorial, -1.0)
         self.assertRaises(ValueError, math.factorial, math.pi)
+        self.assertRaises(OverflowError, math.factorial, sys.maxsize+1)
+        self.assertRaises(OverflowError, math.factorial, 10e100)
 
     def testFloor(self):
         self.assertRaises(TypeError, math.floor)