Issue #10337: skip tests of tanh() sign in test_math and test_cmath if tanh()
doesn't preserve the zero sign (if TANH_PRESERVES_ZERO_SIGN define is 0).
diff --git a/Lib/test/cmath_testcases.txt b/Lib/test/cmath_testcases.txt
index e159380..ce03232 100644
--- a/Lib/test/cmath_testcases.txt
+++ b/Lib/test/cmath_testcases.txt
@@ -1858,11 +1858,14 @@
-- tanh: Hyperbolic Tangent --
------------------------------
--- zeros
-tanh0000 tanh 0.0 0.0 -> 0.0 0.0
-tanh0001 tanh 0.0 -0.0 -> 0.0 -0.0
-tanh0002 tanh -0.0 0.0 -> -0.0 0.0
-tanh0003 tanh -0.0 -0.0 -> -0.0 -0.0
+-- Disabled test: replaced by test_math.testTanhSign()
+-- and test_cmath.testTanhSign()
+
+-- -- zeros
+-- tanh0000 tanh 0.0 0.0 -> 0.0 0.0
+-- tanh0001 tanh 0.0 -0.0 -> 0.0 -0.0
+-- tanh0002 tanh -0.0 0.0 -> -0.0 0.0
+-- tanh0003 tanh -0.0 -0.0 -> -0.0 -0.0
-- random inputs
tanh0004 tanh -21.200500450664993 -1.6970729480342996 -> -1.0 1.9241352344849399e-19
diff --git a/Lib/test/test_cmath.py b/Lib/test/test_cmath.py
index a803363..e3cf03e 100644
--- a/Lib/test/test_cmath.py
+++ b/Lib/test/test_cmath.py
@@ -1,8 +1,9 @@
from test.support import run_unittest
-from test.test_math import parse_testfile, test_file
+from test.test_math import parse_testfile, test_file, requires_IEEE_754
import unittest
import cmath, math
from cmath import phase, polar, rect, pi
+import sysconfig
INF = float('inf')
NAN = float('nan')
@@ -61,6 +62,12 @@
def tearDown(self):
self.test_values.close()
+ def assertComplexIdentical(self, a, b):
+ """Fail if two complex numbers value or sign is different."""
+ self.assertEqual(a, b)
+ self.assertEqual(math.copysign(1., a.real), math.copysign(1., b.real))
+ self.assertEqual(math.copysign(1., a.imag), math.copysign(1., b.imag))
+
def rAssertAlmostEqual(self, a, b, rel_err = 2e-15, abs_err = 5e-323,
msg=None):
"""Fail if the two floating-point numbers are not almost equal.
@@ -473,6 +480,15 @@
self.assertTrue(cmath.isinf(complex(NAN, INF)))
self.assertTrue(cmath.isinf(complex(INF, NAN)))
+ @requires_IEEE_754
+ @unittest.skipIf(sysconfig.get_config_var('TANH_PRESERVES_ZERO_SIGN') == 0,
+ "system tanh() function doesn't copy the sign")
+ def testTanhSign(self):
+ self.assertComplexIdentical(cmath.tanh(complex(0., .0j)), complex(0., .0j))
+ self.assertComplexIdentical(cmath.tanh(complex(0., -.0j)), complex(0., -.0j))
+ self.assertComplexIdentical(cmath.tanh(complex(-0., .0j)), complex(-0., .0j))
+ self.assertComplexIdentical(cmath.tanh(complex(-0., -.0j)), complex(-0., -.0j))
+
def test_main():
run_unittest(CMathTests)
diff --git a/Lib/test/test_math.py b/Lib/test/test_math.py
index 1499ff9..b7a516c 100644
--- a/Lib/test/test_math.py
+++ b/Lib/test/test_math.py
@@ -8,6 +8,7 @@
import sys
import random
import struct
+import sysconfig
eps = 1E-05
NAN = float('nan')
@@ -891,11 +892,15 @@
self.ftest('tanh(inf)', math.tanh(INF), 1)
self.ftest('tanh(-inf)', math.tanh(NINF), -1)
self.assertTrue(math.isnan(math.tanh(NAN)))
+
+ @requires_IEEE_754
+ @unittest.skipIf(sysconfig.get_config_var('TANH_PRESERVES_ZERO_SIGN') == 0,
+ "system tanh() function doesn't copy the sign")
+ def testTanhSign(self):
# check that tanh(-0.) == -0. on IEEE 754 systems
- if float.__getformat__("double").startswith("IEEE"):
- self.assertEqual(math.tanh(-0.), -0.)
- self.assertEqual(math.copysign(1., math.tanh(-0.)),
- math.copysign(1., -0.))
+ self.assertEqual(math.tanh(-0.), -0.)
+ self.assertEqual(math.copysign(1., math.tanh(-0.)),
+ math.copysign(1., -0.))
def test_trunc(self):
self.assertEqual(math.trunc(1), 1)
@@ -1008,8 +1013,7 @@
self.fail(message)
self.ftest("%s:%s(%r)" % (id, fn, ar), result, er)
- @unittest.skipUnless(float.__getformat__("double").startswith("IEEE"),
- "test requires IEEE 754 doubles")
+ @requires_IEEE_754
def test_mtestfile(self):
ALLOWED_ERROR = 20 # permitted error, in ulps
fail_fmt = "{}:{}({!r}): expected {!r}, got {!r}"