Make test_math error messages more meaningful for small discrepancies in results

diff --git a/Lib/test/test_math.py b/Lib/test/test_math.py
index 699c621bcc80816cf6e5742b00c2686f8c233324..d86298d01bd80a4f6c51b6f06ab11a9a142c0f29 100644 (file)
--- a/Lib/test/test_math.py
+++ b/Lib/test/test_math.py
@@ -12,7 +12,11 @@ class MathTests(unittest.TestCase):
 
     def ftest(self, name, value, expected):
         if abs(value-expected) > eps:
-            self.fail('%s returned %f, expected %f'%\
+            # Use %r instead of %f so the error message
+            # displays full precision. Otherwise discrepancies
+            # in the last few bits will lead to very confusing
+            # error messages
+            self.fail('%s returned %r, expected %r' %
                       (name, value, expected))
 
     def testConstants(self):