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Issue 1678380: fix a bug identifying -0.0 and 0.0

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This commit is contained in:
Mark Dickinson 2008-01-21 21:54:47 +00:00
parent 78d50ccdf9
commit 2bebadfe51
3 changed files with 38 additions and 1 deletions
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21
Lib/test/test_float.py
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@ -99,6 +99,27 @@ class IEEEFormatTestCase(unittest.TestCase):
('<f', LE_FLOAT_NAN)]:
struct.unpack(fmt, data)
if float.__getformat__("double").startswith("IEEE"):
def test_negative_zero(self):
import math
def pos_pos():
return 0.0, math.atan2(0.0, -1)
def pos_neg():
return 0.0, math.atan2(-0.0, -1)
def neg_pos():
return -0.0, math.atan2(0.0, -1)
def neg_neg():
return -0.0, math.atan2(-0.0, -1)
self.assertEquals(pos_pos(), neg_pos())
self.assertEquals(pos_neg(), neg_neg())
if float.__getformat__("double").startswith("IEEE"):
def test_underflow_sign(self):
import math
# check that -1e-1000 gives -0.0, not 0.0
self.assertEquals(math.atan2(-1e-1000, -1), math.atan2(-0.0, -1))
self.assertEquals(math.atan2(float('-1e-1000'), -1),
math.atan2(-0.0, -1))
def test_main():
test_support.run_unittest(