diff -r 12c062dbe746 Lib/test/cmath_testcases.txt
--- a/Lib/test/cmath_testcases.txt	Thu Aug 16 22:18:37 2012 +0200
+++ b/Lib/test/cmath_testcases.txt	Fri Aug 17 15:37:11 2012 -0400
@@ -849,7 +849,6 @@
 atan0304 atan -9.9998886718268301e-321 -1.0 -> -0.78539816339744828 -368.76019403576692
 
 -- special values
-atan1000 atan -0.0 0.0 -> -0.0 0.0
 atan1001 atan nan 0.0 -> nan 0.0
 atan1002 atan -0.0 1.0 -> -0.0 inf divide-by-zero
 atan1003 atan -inf 0.0 -> -1.5707963267948966 0.0
@@ -863,7 +862,6 @@
 atan1011 atan -2.2999999999999998 nan -> nan nan
 atan1012 atan -inf nan -> -1.5707963267948966 0.0 ignore-imag-sign
 atan1013 atan nan nan -> nan nan
-atan1014 atan 0.0 0.0 -> 0.0 0.0
 atan1015 atan 0.0 1.0 -> 0.0 inf divide-by-zero
 atan1016 atan inf 0.0 -> 1.5707963267948966 0.0
 atan1017 atan inf 2.2999999999999998 -> 1.5707963267948966 0.0
@@ -873,7 +871,6 @@
 atan1021 atan 0.0 nan -> nan nan
 atan1022 atan 2.2999999999999998 nan -> nan nan
 atan1023 atan inf nan -> 1.5707963267948966 0.0 ignore-imag-sign
-atan1024 atan 0.0 -0.0 -> 0.0 -0.0
 atan1025 atan nan -0.0 -> nan -0.0
 atan1026 atan 0.0 -1.0 -> 0.0 -inf divide-by-zero
 atan1027 atan inf -0.0 -> 1.5707963267948966 -0.0
@@ -883,7 +880,6 @@
 atan1031 atan 2.2999999999999998 -inf -> 1.5707963267948966 -0.0
 atan1032 atan inf -inf -> 1.5707963267948966 -0.0
 atan1033 atan nan -inf -> nan -0.0
-atan1034 atan -0.0 -0.0 -> -0.0 -0.0
 atan1035 atan -0.0 -1.0 -> -0.0 -inf divide-by-zero
 atan1036 atan -inf -0.0 -> -1.5707963267948966 -0.0
 atan1037 atan -inf -2.2999999999999998 -> -1.5707963267948966 -0.0
@@ -1011,9 +1007,7 @@
 atanh0222 atanh -5.9656816081325078e-317 9.9692253555416263e-313 -> -5.9656816081325078e-317 9.9692253555416263e-313
 atanh0223 atanh -6.5606671178400239e-313 -2.1680936406357335e-309 -> -6.5606671178400239e-313 -2.1680936406357335e-309
 atanh0224 atanh 0.0 2.5230944401820779e-319 -> 0.0 2.5230944401820779e-319
-atanh0225 atanh -0.0 5.6066569490064658e-320 -> -0.0 5.6066569490064658e-320
 atanh0226 atanh 0.0 -2.4222487249468377e-317 -> 0.0 -2.4222487249468377e-317
-atanh0227 atanh -0.0 -3.0861101089206037e-316 -> -0.0 -3.0861101089206037e-316
 atanh0228 atanh 3.1219222884393986e-310 0.0 -> 3.1219222884393986e-310 0.0
 atanh0229 atanh 9.8926337564976196e-309 -0.0 -> 9.8926337564976196e-309 -0.0
 atanh0230 atanh -1.5462535092918154e-312 0.0 -> -1.5462535092918154e-312 0.0
@@ -1051,7 +1045,6 @@
 atanh1021 atanh nan -0.0 -> nan nan
 atanh1022 atanh nan -2.3 -> nan nan
 atanh1023 atanh nan -inf -> 0.0 -1.5707963267948966     ignore-real-sign
-atanh1024 atanh -0.0 -0.0 -> -0.0 -0.0
 atanh1025 atanh -0.0 nan -> -0.0 nan
 atanh1026 atanh -1.0 -0.0 -> -inf -0.0                  divide-by-zero
 atanh1027 atanh -0.0 -inf -> -0.0 -1.5707963267948966
@@ -1061,7 +1054,6 @@
 atanh1031 atanh -inf -2.3 -> -0.0 -1.5707963267948966
 atanh1032 atanh -inf -inf -> -0.0 -1.5707963267948966
 atanh1033 atanh -inf nan -> -0.0 nan
-atanh1034 atanh -0.0 0.0 -> -0.0 0.0
 atanh1035 atanh -1.0 0.0 -> -inf 0.0                    divide-by-zero
 atanh1036 atanh -0.0 inf -> -0.0 1.5707963267948966
 atanh1037 atanh -2.3 inf -> -0.0 1.5707963267948966
diff -r 12c062dbe746 Lib/test/test_cmath.py
--- a/Lib/test/test_cmath.py	Thu Aug 16 22:18:37 2012 +0200
+++ b/Lib/test/test_cmath.py	Fri Aug 17 15:37:11 2012 -0400
@@ -532,6 +532,36 @@
         for z in complex_zeros:
             self.assertComplexIdentical(cmath.atanh(z), z)
 
+    @requires_IEEE_754
+    @unittest.skipIf(sysconfig.get_config_var('LOG1P_DROPS_ZERO_SIGN'),
+                     "system log1p() function doesn't preserve the sign")
+    def testAtanhSignNearZero(self):
+        for z in (-30861101e-316, 5.6067e-320):
+            expected = complex(-0.0, z)
+            actual = cmath.atanh(complex(-0.0, z))
+            error_message = (
+                'Expected: complex({!r}, {!r})\n'
+                'Received: complex({!r}, {!r})\n'
+                'Received value insufficiently close to expected value.'
+                ).format(
+                    expected.real,
+                    expected.imag,
+                    actual.real,
+                    actual.imag
+                )
+
+            self.rAssertAlmostEqual(
+                expected.real,
+                actual.real,
+                abs_err=5e-323,
+                msg=error_message,
+            )
+
+            self.rAssertAlmostEqual(
+                expected.imag,
+                actual.imag,
+                msg=error_message,
+            )
 
 def test_main():
     run_unittest(CMathTests)