Make floating-point exception error messages slightly more verbose: in
particular, the error message now allows one to distinguish between a
ValueError arising from a singularity (e.g. log(0.)), which would
usually produce +-infinity in non-stop mode, and a ValueError resulting
from an invalid input (e.g. sqrt(-1.)), which would normally produce a
NaN in non-stop mode.
diff --git a/Lib/test/test_math.py b/Lib/test/test_math.py
index da8a0e9..379ff89 100644
--- a/Lib/test/test_math.py
+++ b/Lib/test/test_math.py
@@ -741,9 +741,9 @@
             func = getattr(math, fn)
             try:
                 result = func(ar)
-            except ValueError:
-                message = ("Unexpected ValueError in " +
-                           "test %s:%s(%r)\n" % (id, fn, ar))
+            except ValueError as exc:
+                message = (("Unexpected ValueError: %s\n        " +
+                           "in test %s:%s(%r)\n") % (exc.args[0], id, fn, ar))
                 self.fail(message)
             self.ftest("%s:%s(%r)" % (id, fn, ar), result, er)