From: Mark Dickinson <mdickinson@enthought.com>
Date: Mon, 9 May 2011 13:02:45 +0000 (+0100)
Subject: Issue #11188: In log2 tests, create powers of 2 using ldexp(1, n) instead of the... 
X-Git-Tag: v3.3.0a1~2338
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=df77e3d4a07223ebfe049e66d4d8a8c0b4315e04;p=python

Issue #11188: In log2 tests, create powers of 2 using ldexp(1, n) instead of the less reliable 2.0**n.
---

diff --git a/Lib/test/test_math.py b/Lib/test/test_math.py
index 3b80bb6c6f..81080f2d1f 100644
--- a/Lib/test/test_math.py
+++ b/Lib/test/test_math.py
@@ -653,8 +653,8 @@ class MathTests(unittest.TestCase):
     def testLog2(self):
         self.assertRaises(TypeError, math.log2)
         # Check that we get exact equality for log2 of powers of 2.
-        actual = [math.log2(2.0**n) for n in range(-324, 1024)]
-        expected = [float(n) for n in range(-324, 1024)]
+        actual = [math.log2(math.ldexp(1.0, n)) for n in range(-1074, 1024)]
+        expected = [float(n) for n in range(-1074, 1024)]
         self.assertEqual(actual, expected)
 
         # Check some integer values