mirror of
https://github.com/python/cpython.git
synced 2025-07-29 22:24:49 +00:00
bf9f4d8015
makes the float constructor behave in the same way as specified by various other language standards, including C99, IEEE 754r, and the IBM Decimal standard.
357 lines
14 KiB
Python
357 lines
14 KiB
Python
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import unittest, struct
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import os
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from test import test_support
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import math
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from math import isinf, isnan
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import operator
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INF = float("inf")
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NAN = float("nan")
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class GeneralFloatCases(unittest.TestCase):
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def test_float(self):
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self.assertEqual(float(3.14), 3.14)
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self.assertEqual(float(314), 314.0)
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self.assertEqual(float(314L), 314.0)
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self.assertEqual(float(" 3.14 "), 3.14)
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self.assertRaises(ValueError, float, " 0x3.1 ")
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self.assertRaises(ValueError, float, " -0x3.p-1 ")
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self.assertRaises(ValueError, float, " +0x3.p-1 ")
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self.assertRaises(ValueError, float, "++3.14")
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self.assertRaises(ValueError, float, "+-3.14")
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self.assertRaises(ValueError, float, "-+3.14")
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self.assertRaises(ValueError, float, "--3.14")
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if have_unicode:
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self.assertEqual(float(unicode(" 3.14 ")), 3.14)
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self.assertEqual(float(unicode(" \u0663.\u0661\u0664 ",'raw-unicode-escape')), 3.14)
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# Implementation limitation in PyFloat_FromString()
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self.assertRaises(ValueError, float, unicode("1"*10000))
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@test_support.run_with_locale('LC_NUMERIC', 'fr_FR', 'de_DE')
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def test_float_with_comma(self):
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# set locale to something that doesn't use '.' for the decimal point
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# float must not accept the locale specific decimal point but
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# it still has to accept the normal python syntac
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import locale
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if not locale.localeconv()['decimal_point'] == ',':
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return
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self.assertEqual(float(" 3.14 "), 3.14)
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self.assertEqual(float("+3.14 "), 3.14)
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self.assertEqual(float("-3.14 "), -3.14)
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self.assertEqual(float(".14 "), .14)
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self.assertEqual(float("3. "), 3.0)
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self.assertEqual(float("3.e3 "), 3000.0)
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self.assertEqual(float("3.2e3 "), 3200.0)
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self.assertEqual(float("2.5e-1 "), 0.25)
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self.assertEqual(float("5e-1"), 0.5)
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self.assertRaises(ValueError, float, " 3,14 ")
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self.assertRaises(ValueError, float, " +3,14 ")
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self.assertRaises(ValueError, float, " -3,14 ")
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self.assertRaises(ValueError, float, " 0x3.1 ")
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self.assertRaises(ValueError, float, " -0x3.p-1 ")
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self.assertRaises(ValueError, float, " +0x3.p-1 ")
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self.assertEqual(float(" 25.e-1 "), 2.5)
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self.assertEqual(fcmp(float(" .25e-1 "), .025), 0)
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def test_floatconversion(self):
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# Make sure that calls to __float__() work properly
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class Foo0:
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def __float__(self):
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return 42.
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class Foo1(object):
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def __float__(self):
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return 42.
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class Foo2(float):
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def __float__(self):
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return 42.
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class Foo3(float):
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def __new__(cls, value=0.):
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return float.__new__(cls, 2*value)
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def __float__(self):
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return self
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class Foo4(float):
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def __float__(self):
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return 42
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self.assertAlmostEqual(float(Foo0()), 42.)
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self.assertAlmostEqual(float(Foo1()), 42.)
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self.assertAlmostEqual(float(Foo2()), 42.)
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self.assertAlmostEqual(float(Foo3(21)), 42.)
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self.assertRaises(TypeError, float, Foo4(42))
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def test_floatasratio(self):
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for f, ratio in [
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(0.875, (7, 8)),
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(-0.875, (-7, 8)),
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(0.0, (0, 1)),
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(11.5, (23, 2)),
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]:
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self.assertEqual(f.as_integer_ratio(), ratio)
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for i in range(10000):
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f = random.random()
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f *= 10 ** random.randint(-100, 100)
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n, d = f.as_integer_ratio()
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self.assertEqual(float(n).__truediv__(d), f)
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R = fractions.Fraction
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self.assertEqual(R(0, 1),
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R(*float(0.0).as_integer_ratio()))
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self.assertEqual(R(5, 2),
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R(*float(2.5).as_integer_ratio()))
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self.assertEqual(R(1, 2),
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R(*float(0.5).as_integer_ratio()))
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self.assertEqual(R(4728779608739021, 2251799813685248),
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R(*float(2.1).as_integer_ratio()))
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self.assertEqual(R(-4728779608739021, 2251799813685248),
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R(*float(-2.1).as_integer_ratio()))
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self.assertEqual(R(-2100, 1),
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R(*float(-2100.0).as_integer_ratio()))
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self.assertRaises(OverflowError, float('inf').as_integer_ratio)
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self.assertRaises(OverflowError, float('-inf').as_integer_ratio)
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self.assertRaises(ValueError, float('nan').as_integer_ratio)
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class FormatFunctionsTestCase(unittest.TestCase):
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def setUp(self):
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self.save_formats = {'double':float.__getformat__('double'),
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'float':float.__getformat__('float')}
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def tearDown(self):
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float.__setformat__('double', self.save_formats['double'])
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float.__setformat__('float', self.save_formats['float'])
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def test_getformat(self):
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self.assert_(float.__getformat__('double') in
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['unknown', 'IEEE, big-endian', 'IEEE, little-endian'])
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self.assert_(float.__getformat__('float') in
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['unknown', 'IEEE, big-endian', 'IEEE, little-endian'])
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self.assertRaises(ValueError, float.__getformat__, 'chicken')
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self.assertRaises(TypeError, float.__getformat__, 1)
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def test_setformat(self):
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for t in 'double', 'float':
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float.__setformat__(t, 'unknown')
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if self.save_formats[t] == 'IEEE, big-endian':
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self.assertRaises(ValueError, float.__setformat__,
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t, 'IEEE, little-endian')
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elif self.save_formats[t] == 'IEEE, little-endian':
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self.assertRaises(ValueError, float.__setformat__,
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t, 'IEEE, big-endian')
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else:
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self.assertRaises(ValueError, float.__setformat__,
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t, 'IEEE, big-endian')
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self.assertRaises(ValueError, float.__setformat__,
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t, 'IEEE, little-endian')
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self.assertRaises(ValueError, float.__setformat__,
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t, 'chicken')
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self.assertRaises(ValueError, float.__setformat__,
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'chicken', 'unknown')
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BE_DOUBLE_INF = '\x7f\xf0\x00\x00\x00\x00\x00\x00'
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LE_DOUBLE_INF = ''.join(reversed(BE_DOUBLE_INF))
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BE_DOUBLE_NAN = '\x7f\xf8\x00\x00\x00\x00\x00\x00'
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LE_DOUBLE_NAN = ''.join(reversed(BE_DOUBLE_NAN))
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BE_FLOAT_INF = '\x7f\x80\x00\x00'
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LE_FLOAT_INF = ''.join(reversed(BE_FLOAT_INF))
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BE_FLOAT_NAN = '\x7f\xc0\x00\x00'
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LE_FLOAT_NAN = ''.join(reversed(BE_FLOAT_NAN))
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# on non-IEEE platforms, attempting to unpack a bit pattern
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# representing an infinity or a NaN should raise an exception.
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class UnknownFormatTestCase(unittest.TestCase):
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def setUp(self):
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self.save_formats = {'double':float.__getformat__('double'),
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'float':float.__getformat__('float')}
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float.__setformat__('double', 'unknown')
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float.__setformat__('float', 'unknown')
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def tearDown(self):
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float.__setformat__('double', self.save_formats['double'])
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float.__setformat__('float', self.save_formats['float'])
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def test_double_specials_dont_unpack(self):
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for fmt, data in [('>d', BE_DOUBLE_INF),
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('>d', BE_DOUBLE_NAN),
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('<d', LE_DOUBLE_INF),
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('<d', LE_DOUBLE_NAN)]:
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self.assertRaises(ValueError, struct.unpack, fmt, data)
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def test_float_specials_dont_unpack(self):
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for fmt, data in [('>f', BE_FLOAT_INF),
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('>f', BE_FLOAT_NAN),
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('<f', LE_FLOAT_INF),
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('<f', LE_FLOAT_NAN)]:
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self.assertRaises(ValueError, struct.unpack, fmt, data)
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# on an IEEE platform, all we guarantee is that bit patterns
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# representing infinities or NaNs do not raise an exception; all else
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# is accident (today).
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# let's also try to guarantee that -0.0 and 0.0 don't get confused.
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class IEEEFormatTestCase(unittest.TestCase):
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if float.__getformat__("double").startswith("IEEE"):
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def test_double_specials_do_unpack(self):
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for fmt, data in [('>d', BE_DOUBLE_INF),
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('>d', BE_DOUBLE_NAN),
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('<d', LE_DOUBLE_INF),
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('<d', LE_DOUBLE_NAN)]:
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struct.unpack(fmt, data)
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if float.__getformat__("float").startswith("IEEE"):
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def test_float_specials_do_unpack(self):
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for fmt, data in [('>f', BE_FLOAT_INF),
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('>f', BE_FLOAT_NAN),
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('<f', LE_FLOAT_INF),
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('<f', LE_FLOAT_NAN)]:
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struct.unpack(fmt, data)
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if float.__getformat__("double").startswith("IEEE"):
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def test_negative_zero(self):
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import math
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def pos_pos():
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return 0.0, math.atan2(0.0, -1)
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def pos_neg():
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return 0.0, math.atan2(-0.0, -1)
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def neg_pos():
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return -0.0, math.atan2(0.0, -1)
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def neg_neg():
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return -0.0, math.atan2(-0.0, -1)
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self.assertEquals(pos_pos(), neg_pos())
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self.assertEquals(pos_neg(), neg_neg())
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if float.__getformat__("double").startswith("IEEE"):
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def test_underflow_sign(self):
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import math
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# check that -1e-1000 gives -0.0, not 0.0
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self.assertEquals(math.atan2(-1e-1000, -1), math.atan2(-0.0, -1))
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self.assertEquals(math.atan2(float('-1e-1000'), -1),
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math.atan2(-0.0, -1))
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class ReprTestCase(unittest.TestCase):
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def test_repr(self):
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floats_file = open(os.path.join(os.path.split(__file__)[0],
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'floating_points.txt'))
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for line in floats_file:
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line = line.strip()
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if not line or line.startswith('#'):
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continue
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v = eval(line)
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self.assertEqual(v, eval(repr(v)))
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floats_file.close()
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# Beginning with Python 2.6 float has cross platform compatible
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# ways to create and represent inf and nan
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class InfNanTest(unittest.TestCase):
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def test_inf_from_str(self):
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self.assert_(isinf(float("inf")))
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self.assert_(isinf(float("+inf")))
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self.assert_(isinf(float("-inf")))
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self.assert_(isinf(float("infinity")))
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self.assert_(isinf(float("+infinity")))
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self.assert_(isinf(float("-infinity")))
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self.assertEqual(repr(float("inf")), "inf")
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self.assertEqual(repr(float("+inf")), "inf")
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self.assertEqual(repr(float("-inf")), "-inf")
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self.assertEqual(repr(float("infinity")), "inf")
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self.assertEqual(repr(float("+infinity")), "inf")
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self.assertEqual(repr(float("-infinity")), "-inf")
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self.assertEqual(repr(float("INF")), "inf")
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self.assertEqual(repr(float("+Inf")), "inf")
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self.assertEqual(repr(float("-iNF")), "-inf")
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self.assertEqual(repr(float("Infinity")), "inf")
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self.assertEqual(repr(float("+iNfInItY")), "inf")
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self.assertEqual(repr(float("-INFINITY")), "-inf")
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self.assertEqual(str(float("inf")), "inf")
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self.assertEqual(str(float("+inf")), "inf")
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self.assertEqual(str(float("-inf")), "-inf")
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self.assertEqual(str(float("infinity")), "inf")
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self.assertEqual(str(float("+infinity")), "inf")
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self.assertEqual(str(float("-infinity")), "-inf")
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self.assertRaises(ValueError, float, "info")
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self.assertRaises(ValueError, float, "+info")
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self.assertRaises(ValueError, float, "-info")
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self.assertRaises(ValueError, float, "in")
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self.assertRaises(ValueError, float, "+in")
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self.assertRaises(ValueError, float, "-in")
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self.assertRaises(ValueError, float, "infinit")
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self.assertRaises(ValueError, float, "+Infin")
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self.assertRaises(ValueError, float, "-INFI")
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self.assertRaises(ValueError, float, "infinitys")
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def test_inf_as_str(self):
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self.assertEqual(repr(1e300 * 1e300), "inf")
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self.assertEqual(repr(-1e300 * 1e300), "-inf")
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self.assertEqual(str(1e300 * 1e300), "inf")
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self.assertEqual(str(-1e300 * 1e300), "-inf")
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def test_nan_from_str(self):
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self.assert_(isnan(float("nan")))
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self.assert_(isnan(float("+nan")))
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self.assert_(isnan(float("-nan")))
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self.assertEqual(repr(float("nan")), "nan")
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self.assertEqual(repr(float("+nan")), "nan")
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self.assertEqual(repr(float("-nan")), "nan")
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self.assertEqual(repr(float("NAN")), "nan")
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self.assertEqual(repr(float("+NAn")), "nan")
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self.assertEqual(repr(float("-NaN")), "nan")
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self.assertEqual(str(float("nan")), "nan")
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self.assertEqual(str(float("+nan")), "nan")
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self.assertEqual(str(float("-nan")), "nan")
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self.assertRaises(ValueError, float, "nana")
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self.assertRaises(ValueError, float, "+nana")
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self.assertRaises(ValueError, float, "-nana")
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self.assertRaises(ValueError, float, "na")
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self.assertRaises(ValueError, float, "+na")
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self.assertRaises(ValueError, float, "-na")
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def test_nan_as_str(self):
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self.assertEqual(repr(1e300 * 1e300 * 0), "nan")
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self.assertEqual(repr(-1e300 * 1e300 * 0), "nan")
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self.assertEqual(str(1e300 * 1e300 * 0), "nan")
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self.assertEqual(str(-1e300 * 1e300 * 0), "nan")
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def notest_float_nan(self):
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self.assert_(NAN.is_nan())
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self.failIf(INF.is_nan())
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self.failIf((0.).is_nan())
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def notest_float_inf(self):
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self.assert_(INF.is_inf())
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self.failIf(NAN.is_inf())
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self.failIf((0.).is_inf())
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def test_main():
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test_support.run_unittest(
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FormatFunctionsTestCase,
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UnknownFormatTestCase,
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IEEEFormatTestCase,
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ReprTestCase,
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InfNanTest,
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)
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if __name__ == '__main__':
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test_main()
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