[issue10337] testTanh() of test_math fails on "NetBSD 5 i386 3.x"

[STINNER Victor]

New submission from STINNER Victor <victor.stinner at haypocalc.com>:

On "NetBSD 5 i386 3.x" buildbot, testTanh() of test_math fails because the sign of wrong.

configure scripts has a test to check if tanh(-0.0) keeps the sign or no, and on this buildbot the result is "no". pyconfig.h contains a TANH_PRESERVES_ZERO_SIGN define, but it is not used in Modules/mathmodule.c. Extract of configure comment:

# On FreeBSD 6.2, it appears that tanh(-0.) returns 0. instead of
# -0. on some architectures.

---

http://www.python.org/dev/buildbot/builders/NetBSD%205%20i386%203.x/builds/237/steps/configure/logs/stdio
...
checking whether tanh preserves the sign of zero... no
...

http://www.python.org/dev/buildbot/builders/NetBSD%205%20i386%203.x/builds/237/steps/test/logs/stdio
======================================================================
FAIL: testTanh (test.test_math.MathTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/buildbot/buildarea/3.x.smith-netbsd-i386/build/Lib/test/test_math.py", line 898, in testTanh
    math.copysign(1., -0.))
AssertionError: 1.0 != -1.0

----------------------------------------------------------------------

----------
components: Library (Lib)
messages: 120604
nosy: haypo
priority: normal
severity: normal
status: open
title: testTanh() of test_math fails on "NetBSD 5 i386 3.x"
versions: Python 3.1, Python 3.2

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue10337>
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