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      1 """Tests for Lib/fractions.py."""
      2 
      3 from decimal import Decimal
      4 from test.test_support import run_unittest
      5 import math
      6 import numbers
      7 import operator
      8 import fractions
      9 import unittest
     10 from copy import copy, deepcopy
     11 from cPickle import dumps, loads
     12 F = fractions.Fraction
     13 gcd = fractions.gcd
     14 
     15 # decorator for skipping tests on non-IEEE 754 platforms

     16 requires_IEEE_754 = unittest.skipUnless(
     17     float.__getformat__("double").startswith("IEEE"),
     18     "test requires IEEE 754 doubles")
     19 
     20 class DummyFloat(object):
     21     """Dummy float class for testing comparisons with Fractions"""
     22 
     23     def __init__(self, value):
     24         if not isinstance(value, float):
     25             raise TypeError("DummyFloat can only be initialized from float")
     26         self.value = value
     27 
     28     def _richcmp(self, other, op):
     29         if isinstance(other, numbers.Rational):
     30             return op(F.from_float(self.value), other)
     31         elif isinstance(other, DummyFloat):
     32             return op(self.value, other.value)
     33         else:
     34             return NotImplemented
     35 
     36     def __eq__(self, other): return self._richcmp(other, operator.eq)
     37     def __le__(self, other): return self._richcmp(other, operator.le)
     38     def __lt__(self, other): return self._richcmp(other, operator.lt)
     39     def __ge__(self, other): return self._richcmp(other, operator.ge)
     40     def __gt__(self, other): return self._richcmp(other, operator.gt)
     41 
     42     # shouldn't be calling __float__ at all when doing comparisons

     43     def __float__(self):
     44         assert False, "__float__ should not be invoked for comparisons"
     45 
     46     # same goes for subtraction

     47     def __sub__(self, other):
     48         assert False, "__sub__ should not be invoked for comparisons"
     49     __rsub__ = __sub__
     50 
     51     # Silence Py3k warning

     52     __hash__ = None
     53 
     54 
     55 class DummyRational(object):
     56     """Test comparison of Fraction with a naive rational implementation."""
     57 
     58     def __init__(self, num, den):
     59         g = gcd(num, den)
     60         self.num = num // g
     61         self.den = den // g
     62 
     63     def __eq__(self, other):
     64         if isinstance(other, fractions.Fraction):
     65             return (self.num == other._numerator and
     66                     self.den == other._denominator)
     67         else:
     68             return NotImplemented
     69 
     70     def __lt__(self, other):
     71         return(self.num * other._denominator < self.den * other._numerator)
     72 
     73     def __gt__(self, other):
     74         return(self.num * other._denominator > self.den * other._numerator)
     75 
     76     def __le__(self, other):
     77         return(self.num * other._denominator <= self.den * other._numerator)
     78 
     79     def __ge__(self, other):
     80         return(self.num * other._denominator >= self.den * other._numerator)
     81 
     82     # this class is for testing comparisons; conversion to float

     83     # should never be used for a comparison, since it loses accuracy

     84     def __float__(self):
     85         assert False, "__float__ should not be invoked"
     86 
     87     # Silence Py3k warning

     88     __hash__ = None
     89 
     90 
     91 class GcdTest(unittest.TestCase):
     92 
     93     def testMisc(self):
     94         self.assertEqual(0, gcd(0, 0))
     95         self.assertEqual(1, gcd(1, 0))
     96         self.assertEqual(-1, gcd(-1, 0))
     97         self.assertEqual(1, gcd(0, 1))
     98         self.assertEqual(-1, gcd(0, -1))
     99         self.assertEqual(1, gcd(7, 1))
    100         self.assertEqual(-1, gcd(7, -1))
    101         self.assertEqual(1, gcd(-23, 15))
    102         self.assertEqual(12, gcd(120, 84))
    103         self.assertEqual(-12, gcd(84, -120))
    104 
    105 
    106 def _components(r):
    107     return (r.numerator, r.denominator)
    108 
    109 
    110 class FractionTest(unittest.TestCase):
    111 
    112     def assertTypedEquals(self, expected, actual):
    113         """Asserts that both the types and values are the same."""
    114         self.assertEqual(type(expected), type(actual))
    115         self.assertEqual(expected, actual)
    116 
    117     def assertRaisesMessage(self, exc_type, message,
    118                             callable, *args, **kwargs):
    119         """Asserts that callable(*args, **kwargs) raises exc_type(message)."""
    120         try:
    121             callable(*args, **kwargs)
    122         except exc_type, e:
    123             self.assertEqual(message, str(e))
    124         else:
    125             self.fail("%s not raised" % exc_type.__name__)
    126 
    127     def testInit(self):
    128         self.assertEqual((0, 1), _components(F()))
    129         self.assertEqual((7, 1), _components(F(7)))
    130         self.assertEqual((7, 3), _components(F(F(7, 3))))
    131 
    132         self.assertEqual((-1, 1), _components(F(-1, 1)))
    133         self.assertEqual((-1, 1), _components(F(1, -1)))
    134         self.assertEqual((1, 1), _components(F(-2, -2)))
    135         self.assertEqual((1, 2), _components(F(5, 10)))
    136         self.assertEqual((7, 15), _components(F(7, 15)))
    137         self.assertEqual((10**23, 1), _components(F(10**23)))
    138 
    139         self.assertEqual((3, 77), _components(F(F(3, 7), 11)))
    140         self.assertEqual((-9, 5), _components(F(2, F(-10, 9))))
    141         self.assertEqual((2486, 2485), _components(F(F(22, 7), F(355, 113))))
    142 
    143         self.assertRaisesMessage(ZeroDivisionError, "Fraction(12, 0)",
    144                                  F, 12, 0)
    145         self.assertRaises(TypeError, F, 1.5 + 3j)
    146 
    147         self.assertRaises(TypeError, F, "3/2", 3)
    148         self.assertRaises(TypeError, F, 3, 0j)
    149         self.assertRaises(TypeError, F, 3, 1j)
    150 
    151     @requires_IEEE_754
    152     def testInitFromFloat(self):
    153         self.assertEqual((5, 2), _components(F(2.5)))
    154         self.assertEqual((0, 1), _components(F(-0.0)))
    155         self.assertEqual((3602879701896397, 36028797018963968),
    156                          _components(F(0.1)))
    157         self.assertRaises(TypeError, F, float('nan'))
    158         self.assertRaises(TypeError, F, float('inf'))
    159         self.assertRaises(TypeError, F, float('-inf'))
    160 
    161     def testInitFromDecimal(self):
    162         self.assertEqual((11, 10),
    163                          _components(F(Decimal('1.1'))))
    164         self.assertEqual((7, 200),
    165                          _components(F(Decimal('3.5e-2'))))
    166         self.assertEqual((0, 1),
    167                          _components(F(Decimal('.000e20'))))
    168         self.assertRaises(TypeError, F, Decimal('nan'))
    169         self.assertRaises(TypeError, F, Decimal('snan'))
    170         self.assertRaises(TypeError, F, Decimal('inf'))
    171         self.assertRaises(TypeError, F, Decimal('-inf'))
    172 
    173     def testFromString(self):
    174         self.assertEqual((5, 1), _components(F("5")))
    175         self.assertEqual((3, 2), _components(F("3/2")))
    176         self.assertEqual((3, 2), _components(F(" \n  +3/2")))
    177         self.assertEqual((-3, 2), _components(F("-3/2  ")))
    178         self.assertEqual((13, 2), _components(F("    013/02 \n  ")))
    179         self.assertEqual((13, 2), _components(F(u"    013/02 \n  ")))
    180 
    181         self.assertEqual((16, 5), _components(F(" 3.2 ")))
    182         self.assertEqual((-16, 5), _components(F(u" -3.2 ")))
    183         self.assertEqual((-3, 1), _components(F(u" -3. ")))
    184         self.assertEqual((3, 5), _components(F(u" .6 ")))
    185         self.assertEqual((1, 3125), _components(F("32.e-5")))
    186         self.assertEqual((1000000, 1), _components(F("1E+06")))
    187         self.assertEqual((-12300, 1), _components(F("-1.23e4")))
    188         self.assertEqual((0, 1), _components(F(" .0e+0\t")))
    189         self.assertEqual((0, 1), _components(F("-0.000e0")))
    190 
    191 
    192         self.assertRaisesMessage(
    193             ZeroDivisionError, "Fraction(3, 0)",
    194             F, "3/0")
    195         self.assertRaisesMessage(
    196             ValueError, "Invalid literal for Fraction: '3/'",
    197             F, "3/")
    198         self.assertRaisesMessage(
    199             ValueError, "Invalid literal for Fraction: '/2'",
    200             F, "/2")
    201         self.assertRaisesMessage(
    202             ValueError, "Invalid literal for Fraction: '3 /2'",
    203             F, "3 /2")
    204         self.assertRaisesMessage(
    205             # Denominators don't need a sign.

    206             ValueError, "Invalid literal for Fraction: '3/+2'",
    207             F, "3/+2")
    208         self.assertRaisesMessage(
    209             # Imitate float's parsing.

    210             ValueError, "Invalid literal for Fraction: '+ 3/2'",
    211             F, "+ 3/2")
    212         self.assertRaisesMessage(
    213             # Avoid treating '.' as a regex special character.

    214             ValueError, "Invalid literal for Fraction: '3a2'",
    215             F, "3a2")
    216         self.assertRaisesMessage(
    217             # Don't accept combinations of decimals and fractions.

    218             ValueError, "Invalid literal for Fraction: '3/7.2'",
    219             F, "3/7.2")
    220         self.assertRaisesMessage(
    221             # Don't accept combinations of decimals and fractions.

    222             ValueError, "Invalid literal for Fraction: '3.2/7'",
    223             F, "3.2/7")
    224         self.assertRaisesMessage(
    225             # Allow 3. and .3, but not .

    226             ValueError, "Invalid literal for Fraction: '.'",
    227             F, ".")
    228 
    229     def testImmutable(self):
    230         r = F(7, 3)
    231         r.__init__(2, 15)
    232         self.assertEqual((7, 3), _components(r))
    233 
    234         self.assertRaises(AttributeError, setattr, r, 'numerator', 12)
    235         self.assertRaises(AttributeError, setattr, r, 'denominator', 6)
    236         self.assertEqual((7, 3), _components(r))
    237 
    238         # But if you _really_ need to:

    239         r._numerator = 4
    240         r._denominator = 2
    241         self.assertEqual((4, 2), _components(r))
    242         # Which breaks some important operations:

    243         self.assertNotEqual(F(4, 2), r)
    244 
    245     def testFromFloat(self):
    246         self.assertRaises(TypeError, F.from_float, 3+4j)
    247         self.assertEqual((10, 1), _components(F.from_float(10)))
    248         bigint = 1234567890123456789
    249         self.assertEqual((bigint, 1), _components(F.from_float(bigint)))
    250         self.assertEqual((0, 1), _components(F.from_float(-0.0)))
    251         self.assertEqual((10, 1), _components(F.from_float(10.0)))
    252         self.assertEqual((-5, 2), _components(F.from_float(-2.5)))
    253         self.assertEqual((99999999999999991611392, 1),
    254                          _components(F.from_float(1e23)))
    255         self.assertEqual(float(10**23), float(F.from_float(1e23)))
    256         self.assertEqual((3602879701896397, 1125899906842624),
    257                          _components(F.from_float(3.2)))
    258         self.assertEqual(3.2, float(F.from_float(3.2)))
    259 
    260         inf = 1e1000
    261         nan = inf - inf
    262         self.assertRaisesMessage(
    263             TypeError, "Cannot convert inf to Fraction.",
    264             F.from_float, inf)
    265         self.assertRaisesMessage(
    266             TypeError, "Cannot convert -inf to Fraction.",
    267             F.from_float, -inf)
    268         self.assertRaisesMessage(
    269             TypeError, "Cannot convert nan to Fraction.",
    270             F.from_float, nan)
    271 
    272     def testFromDecimal(self):
    273         self.assertRaises(TypeError, F.from_decimal, 3+4j)
    274         self.assertEqual(F(10, 1), F.from_decimal(10))
    275         self.assertEqual(F(0), F.from_decimal(Decimal("-0")))
    276         self.assertEqual(F(5, 10), F.from_decimal(Decimal("0.5")))
    277         self.assertEqual(F(5, 1000), F.from_decimal(Decimal("5e-3")))
    278         self.assertEqual(F(5000), F.from_decimal(Decimal("5e3")))
    279         self.assertEqual(1 - F(1, 10**30),
    280                          F.from_decimal(Decimal("0." + "9" * 30)))
    281 
    282         self.assertRaisesMessage(
    283             TypeError, "Cannot convert Infinity to Fraction.",
    284             F.from_decimal, Decimal("inf"))
    285         self.assertRaisesMessage(
    286             TypeError, "Cannot convert -Infinity to Fraction.",
    287             F.from_decimal, Decimal("-inf"))
    288         self.assertRaisesMessage(
    289             TypeError, "Cannot convert NaN to Fraction.",
    290             F.from_decimal, Decimal("nan"))
    291         self.assertRaisesMessage(
    292             TypeError, "Cannot convert sNaN to Fraction.",
    293             F.from_decimal, Decimal("snan"))
    294 
    295     def testLimitDenominator(self):
    296         rpi = F('3.1415926535897932')
    297         self.assertEqual(rpi.limit_denominator(10000), F(355, 113))
    298         self.assertEqual(-rpi.limit_denominator(10000), F(-355, 113))
    299         self.assertEqual(rpi.limit_denominator(113), F(355, 113))
    300         self.assertEqual(rpi.limit_denominator(112), F(333, 106))
    301         self.assertEqual(F(201, 200).limit_denominator(100), F(1))
    302         self.assertEqual(F(201, 200).limit_denominator(101), F(102, 101))
    303         self.assertEqual(F(0).limit_denominator(10000), F(0))
    304 
    305     def testConversions(self):
    306         self.assertTypedEquals(-1, math.trunc(F(-11, 10)))
    307         self.assertTypedEquals(-1, int(F(-11, 10)))
    308 
    309         self.assertEqual(False, bool(F(0, 1)))
    310         self.assertEqual(True, bool(F(3, 2)))
    311         self.assertTypedEquals(0.1, float(F(1, 10)))
    312 
    313         # Check that __float__ isn't implemented by converting the

    314         # numerator and denominator to float before dividing.

    315         self.assertRaises(OverflowError, float, long('2'*400+'7'))
    316         self.assertAlmostEqual(2.0/3,
    317                                 float(F(long('2'*400+'7'), long('3'*400+'1'))))
    318 
    319         self.assertTypedEquals(0.1+0j, complex(F(1,10)))
    320 
    321 
    322     def testArithmetic(self):
    323         self.assertEqual(F(1, 2), F(1, 10) + F(2, 5))
    324         self.assertEqual(F(-3, 10), F(1, 10) - F(2, 5))
    325         self.assertEqual(F(1, 25), F(1, 10) * F(2, 5))
    326         self.assertEqual(F(1, 4), F(1, 10) / F(2, 5))
    327         self.assertTypedEquals(2, F(9, 10) // F(2, 5))
    328         self.assertTypedEquals(10**23, F(10**23, 1) // F(1))
    329         self.assertEqual(F(2, 3), F(-7, 3) % F(3, 2))
    330         self.assertEqual(F(8, 27), F(2, 3) ** F(3))
    331         self.assertEqual(F(27, 8), F(2, 3) ** F(-3))
    332         self.assertTypedEquals(2.0, F(4) ** F(1, 2))
    333         # Will return 1j in 3.0:

    334         self.assertRaises(ValueError, pow, F(-1), F(1, 2))
    335 
    336     def testMixedArithmetic(self):
    337         self.assertTypedEquals(F(11, 10), F(1, 10) + 1)
    338         self.assertTypedEquals(1.1, F(1, 10) + 1.0)
    339         self.assertTypedEquals(1.1 + 0j, F(1, 10) + (1.0 + 0j))
    340         self.assertTypedEquals(F(11, 10), 1 + F(1, 10))
    341         self.assertTypedEquals(1.1, 1.0 + F(1, 10))
    342         self.assertTypedEquals(1.1 + 0j, (1.0 + 0j) + F(1, 10))
    343 
    344         self.assertTypedEquals(F(-9, 10), F(1, 10) - 1)
    345         self.assertTypedEquals(-0.9, F(1, 10) - 1.0)
    346         self.assertTypedEquals(-0.9 + 0j, F(1, 10) - (1.0 + 0j))
    347         self.assertTypedEquals(F(9, 10), 1 - F(1, 10))
    348         self.assertTypedEquals(0.9, 1.0 - F(1, 10))
    349         self.assertTypedEquals(0.9 + 0j, (1.0 + 0j) - F(1, 10))
    350 
    351         self.assertTypedEquals(F(1, 10), F(1, 10) * 1)
    352         self.assertTypedEquals(0.1, F(1, 10) * 1.0)
    353         self.assertTypedEquals(0.1 + 0j, F(1, 10) * (1.0 + 0j))
    354         self.assertTypedEquals(F(1, 10), 1 * F(1, 10))
    355         self.assertTypedEquals(0.1, 1.0 * F(1, 10))
    356         self.assertTypedEquals(0.1 + 0j, (1.0 + 0j) * F(1, 10))
    357 
    358         self.assertTypedEquals(F(1, 10), F(1, 10) / 1)
    359         self.assertTypedEquals(0.1, F(1, 10) / 1.0)
    360         self.assertTypedEquals(0.1 + 0j, F(1, 10) / (1.0 + 0j))
    361         self.assertTypedEquals(F(10, 1), 1 / F(1, 10))
    362         self.assertTypedEquals(10.0, 1.0 / F(1, 10))
    363         self.assertTypedEquals(10.0 + 0j, (1.0 + 0j) / F(1, 10))
    364 
    365         self.assertTypedEquals(0, F(1, 10) // 1)
    366         self.assertTypedEquals(0.0, F(1, 10) // 1.0)
    367         self.assertTypedEquals(10, 1 // F(1, 10))
    368         self.assertTypedEquals(10**23, 10**22 // F(1, 10))
    369         self.assertTypedEquals(10.0, 1.0 // F(1, 10))
    370 
    371         self.assertTypedEquals(F(1, 10), F(1, 10) % 1)
    372         self.assertTypedEquals(0.1, F(1, 10) % 1.0)
    373         self.assertTypedEquals(F(0, 1), 1 % F(1, 10))
    374         self.assertTypedEquals(0.0, 1.0 % F(1, 10))
    375 
    376         # No need for divmod since we don't override it.

    377 
    378         # ** has more interesting conversion rules.

    379         self.assertTypedEquals(F(100, 1), F(1, 10) ** -2)
    380         self.assertTypedEquals(F(100, 1), F(10, 1) ** 2)
    381         self.assertTypedEquals(0.1, F(1, 10) ** 1.0)
    382         self.assertTypedEquals(0.1 + 0j, F(1, 10) ** (1.0 + 0j))
    383         self.assertTypedEquals(4 , 2 ** F(2, 1))
    384         # Will return 1j in 3.0:

    385         self.assertRaises(ValueError, pow, (-1), F(1, 2))
    386         self.assertTypedEquals(F(1, 4) , 2 ** F(-2, 1))
    387         self.assertTypedEquals(2.0 , 4 ** F(1, 2))
    388         self.assertTypedEquals(0.25, 2.0 ** F(-2, 1))
    389         self.assertTypedEquals(1.0 + 0j, (1.0 + 0j) ** F(1, 10))
    390 
    391     def testMixingWithDecimal(self):
    392         # Decimal refuses mixed comparisons.

    393         self.assertRaisesMessage(
    394             TypeError,
    395             "unsupported operand type(s) for +: 'Fraction' and 'Decimal'",
    396             operator.add, F(3,11), Decimal('3.1415926'))
    397         self.assertNotEqual(F(5, 2), Decimal('2.5'))
    398 
    399     def testComparisons(self):
    400         self.assertTrue(F(1, 2) < F(2, 3))
    401         self.assertFalse(F(1, 2) < F(1, 2))
    402         self.assertTrue(F(1, 2) <= F(2, 3))
    403         self.assertTrue(F(1, 2) <= F(1, 2))
    404         self.assertFalse(F(2, 3) <= F(1, 2))
    405         self.assertTrue(F(1, 2) == F(1, 2))
    406         self.assertFalse(F(1, 2) == F(1, 3))
    407         self.assertFalse(F(1, 2) != F(1, 2))
    408         self.assertTrue(F(1, 2) != F(1, 3))
    409 
    410     def testComparisonsDummyRational(self):
    411         self.assertTrue(F(1, 2) == DummyRational(1, 2))
    412         self.assertTrue(DummyRational(1, 2) == F(1, 2))
    413         self.assertFalse(F(1, 2) == DummyRational(3, 4))
    414         self.assertFalse(DummyRational(3, 4) == F(1, 2))
    415 
    416         self.assertTrue(F(1, 2) < DummyRational(3, 4))
    417         self.assertFalse(F(1, 2) < DummyRational(1, 2))
    418         self.assertFalse(F(1, 2) < DummyRational(1, 7))
    419         self.assertFalse(F(1, 2) > DummyRational(3, 4))
    420         self.assertFalse(F(1, 2) > DummyRational(1, 2))
    421         self.assertTrue(F(1, 2) > DummyRational(1, 7))
    422         self.assertTrue(F(1, 2) <= DummyRational(3, 4))
    423         self.assertTrue(F(1, 2) <= DummyRational(1, 2))
    424         self.assertFalse(F(1, 2) <= DummyRational(1, 7))
    425         self.assertFalse(F(1, 2) >= DummyRational(3, 4))
    426         self.assertTrue(F(1, 2) >= DummyRational(1, 2))
    427         self.assertTrue(F(1, 2) >= DummyRational(1, 7))
    428 
    429         self.assertTrue(DummyRational(1, 2) < F(3, 4))
    430         self.assertFalse(DummyRational(1, 2) < F(1, 2))
    431         self.assertFalse(DummyRational(1, 2) < F(1, 7))
    432         self.assertFalse(DummyRational(1, 2) > F(3, 4))
    433         self.assertFalse(DummyRational(1, 2) > F(1, 2))
    434         self.assertTrue(DummyRational(1, 2) > F(1, 7))
    435         self.assertTrue(DummyRational(1, 2) <= F(3, 4))
    436         self.assertTrue(DummyRational(1, 2) <= F(1, 2))
    437         self.assertFalse(DummyRational(1, 2) <= F(1, 7))
    438         self.assertFalse(DummyRational(1, 2) >= F(3, 4))
    439         self.assertTrue(DummyRational(1, 2) >= F(1, 2))
    440         self.assertTrue(DummyRational(1, 2) >= F(1, 7))
    441 
    442     def testComparisonsDummyFloat(self):
    443         x = DummyFloat(1./3.)
    444         y = F(1, 3)
    445         self.assertTrue(x != y)
    446         self.assertTrue(x < y or x > y)
    447         self.assertFalse(x == y)
    448         self.assertFalse(x <= y and x >= y)
    449         self.assertTrue(y != x)
    450         self.assertTrue(y < x or y > x)
    451         self.assertFalse(y == x)
    452         self.assertFalse(y <= x and y >= x)
    453 
    454     def testMixedLess(self):
    455         self.assertTrue(2 < F(5, 2))
    456         self.assertFalse(2 < F(4, 2))
    457         self.assertTrue(F(5, 2) < 3)
    458         self.assertFalse(F(4, 2) < 2)
    459 
    460         self.assertTrue(F(1, 2) < 0.6)
    461         self.assertFalse(F(1, 2) < 0.4)
    462         self.assertTrue(0.4 < F(1, 2))
    463         self.assertFalse(0.5 < F(1, 2))
    464 
    465         self.assertFalse(float('inf') < F(1, 2))
    466         self.assertTrue(float('-inf') < F(0, 10))
    467         self.assertFalse(float('nan') < F(-3, 7))
    468         self.assertTrue(F(1, 2) < float('inf'))
    469         self.assertFalse(F(17, 12) < float('-inf'))
    470         self.assertFalse(F(144, -89) < float('nan'))
    471 
    472     def testMixedLessEqual(self):
    473         self.assertTrue(0.5 <= F(1, 2))
    474         self.assertFalse(0.6 <= F(1, 2))
    475         self.assertTrue(F(1, 2) <= 0.5)
    476         self.assertFalse(F(1, 2) <= 0.4)
    477         self.assertTrue(2 <= F(4, 2))
    478         self.assertFalse(2 <= F(3, 2))
    479         self.assertTrue(F(4, 2) <= 2)
    480         self.assertFalse(F(5, 2) <= 2)
    481 
    482         self.assertFalse(float('inf') <= F(1, 2))
    483         self.assertTrue(float('-inf') <= F(0, 10))
    484         self.assertFalse(float('nan') <= F(-3, 7))
    485         self.assertTrue(F(1, 2) <= float('inf'))
    486         self.assertFalse(F(17, 12) <= float('-inf'))
    487         self.assertFalse(F(144, -89) <= float('nan'))
    488 
    489     def testBigFloatComparisons(self):
    490         # Because 10**23 can't be represented exactly as a float:

    491         self.assertFalse(F(10**23) == float(10**23))
    492         # The first test demonstrates why these are important.

    493         self.assertFalse(1e23 < float(F(math.trunc(1e23) + 1)))
    494         self.assertTrue(1e23 < F(math.trunc(1e23) + 1))
    495         self.assertFalse(1e23 <= F(math.trunc(1e23) - 1))
    496         self.assertTrue(1e23 > F(math.trunc(1e23) - 1))
    497         self.assertFalse(1e23 >= F(math.trunc(1e23) + 1))
    498 
    499     def testBigComplexComparisons(self):
    500         self.assertFalse(F(10**23) == complex(10**23))
    501         self.assertRaises(TypeError, operator.gt, F(10**23), complex(10**23))
    502         self.assertRaises(TypeError, operator.le, F(10**23), complex(10**23))
    503 
    504         x = F(3, 8)
    505         z = complex(0.375, 0.0)
    506         w = complex(0.375, 0.2)
    507         self.assertTrue(x == z)
    508         self.assertFalse(x != z)
    509         self.assertFalse(x == w)
    510         self.assertTrue(x != w)
    511         for op in operator.lt, operator.le, operator.gt, operator.ge:
    512             self.assertRaises(TypeError, op, x, z)
    513             self.assertRaises(TypeError, op, z, x)
    514             self.assertRaises(TypeError, op, x, w)
    515             self.assertRaises(TypeError, op, w, x)
    516 
    517     def testMixedEqual(self):
    518         self.assertTrue(0.5 == F(1, 2))
    519         self.assertFalse(0.6 == F(1, 2))
    520         self.assertTrue(F(1, 2) == 0.5)
    521         self.assertFalse(F(1, 2) == 0.4)
    522         self.assertTrue(2 == F(4, 2))
    523         self.assertFalse(2 == F(3, 2))
    524         self.assertTrue(F(4, 2) == 2)
    525         self.assertFalse(F(5, 2) == 2)
    526         self.assertFalse(F(5, 2) == float('nan'))
    527         self.assertFalse(float('nan') == F(3, 7))
    528         self.assertFalse(F(5, 2) == float('inf'))
    529         self.assertFalse(float('-inf') == F(2, 5))
    530 
    531     def testStringification(self):
    532         self.assertEqual("Fraction(7, 3)", repr(F(7, 3)))
    533         self.assertEqual("Fraction(6283185307, 2000000000)",
    534                          repr(F('3.1415926535')))
    535         self.assertEqual("Fraction(-1, 100000000000000000000)",
    536                          repr(F(1, -10**20)))
    537         self.assertEqual("7/3", str(F(7, 3)))
    538         self.assertEqual("7", str(F(7, 1)))
    539 
    540     def testHash(self):
    541         self.assertEqual(hash(2.5), hash(F(5, 2)))
    542         self.assertEqual(hash(10**50), hash(F(10**50)))
    543         self.assertNotEqual(hash(float(10**23)), hash(F(10**23)))
    544 
    545     def testApproximatePi(self):
    546         # Algorithm borrowed from

    547         # http://docs.python.org/lib/decimal-recipes.html

    548         three = F(3)
    549         lasts, t, s, n, na, d, da = 0, three, 3, 1, 0, 0, 24
    550         while abs(s - lasts) > F(1, 10**9):
    551             lasts = s
    552             n, na = n+na, na+8
    553             d, da = d+da, da+32
    554             t = (t * n) / d
    555             s += t
    556         self.assertAlmostEqual(math.pi, s)
    557 
    558     def testApproximateCos1(self):
    559         # Algorithm borrowed from

    560         # http://docs.python.org/lib/decimal-recipes.html

    561         x = F(1)
    562         i, lasts, s, fact, num, sign = 0, 0, F(1), 1, 1, 1
    563         while abs(s - lasts) > F(1, 10**9):
    564             lasts = s
    565             i += 2
    566             fact *= i * (i-1)
    567             num *= x * x
    568             sign *= -1
    569             s += num / fact * sign
    570         self.assertAlmostEqual(math.cos(1), s)
    571 
    572     def test_copy_deepcopy_pickle(self):
    573         r = F(13, 7)
    574         self.assertEqual(r, loads(dumps(r)))
    575         self.assertEqual(id(r), id(copy(r)))
    576         self.assertEqual(id(r), id(deepcopy(r)))
    577 
    578     def test_slots(self):
    579         # Issue 4998

    580         r = F(13, 7)
    581         self.assertRaises(AttributeError, setattr, r, 'a', 10)
    582 
    583 def test_main():
    584     run_unittest(FractionTest, GcdTest)
    585 
    586 if __name__ == '__main__':
    587     test_main()
    588