Use skipUnless to skip math module tests on non-IEEE 754 platforms.

Lib/test/test_math.py

@@ -13,6 +13,11 @@ NAN = float('nan')
 INF = float('inf')
 NINF = float('-inf')
 
+# decorator for skipping tests on non-IEEE 754 platforms
+requires_IEEE_754 = unittest.skipUnless(
+    float.__getformat__("double").startswith("IEEE"),
+    "test requires IEEE 754 doubles")
+
 # detect evidence of double-rounding: fsum is not always correctly
 # rounded on machines that suffer from double rounding.
 x, y = 1e16, 2.9999 # use temporary values to defeat peephole optimizer
@@ -212,7 +217,7 @@ class MathTests(unittest.TestCase):
         self.assertRaises(TypeError, math.ceil, t)
         self.assertRaises(TypeError, math.ceil, t, 0)
 
-    if float.__getformat__("double").startswith("IEEE"):
+    @requires_IEEE_754
     def testCopysign(self):
         self.assertRaises(TypeError, math.copysign)
         # copysign should let us distinguish signs of zeros
@@ -369,8 +374,7 @@ class MathTests(unittest.TestCase):
         self.assertEquals(math.frexp(NINF)[0], NINF)
         self.assertTrue(math.isnan(math.frexp(NAN)[0]))
 
-    @unittest.skipUnless(float.__getformat__("double").startswith("IEEE"),
-                         "test requires IEEE 754 doubles")
+    @requires_IEEE_754
     @unittest.skipIf(HAVE_DOUBLE_ROUNDING,
                          "fsum is not exact on machines with double rounding")
     def testFsum(self):
@@ -860,9 +864,8 @@ class MathTests(unittest.TestCase):
             else:
                 self.fail("sqrt(-1) didn't raise ValueError")
 
+    @requires_IEEE_754
     def test_testfile(self):
-        if not float.__getformat__("double").startswith("IEEE"):
-            return
         for id, fn, ar, ai, er, ei, flags in parse_testfile(test_file):
             # Skip if either the input or result is complex, or if
             # flags is nonempty