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- # test interactions between int, float, Decimal and Fraction
- import unittest
- import random
- import math
- import sys
- import operator
- from decimal import Decimal as D
- from fractions import Fraction as F
- # Constants related to the hash implementation; hash(x) is based
- # on the reduction of x modulo the prime _PyHASH_MODULUS.
- _PyHASH_MODULUS = sys.hash_info.modulus
- _PyHASH_INF = sys.hash_info.inf
- class DummyIntegral(int):
- """Dummy Integral class to test conversion of the Rational to float."""
- def __mul__(self, other):
- return DummyIntegral(super().__mul__(other))
- __rmul__ = __mul__
- def __truediv__(self, other):
- return NotImplemented
- __rtruediv__ = __truediv__
- @property
- def numerator(self):
- return DummyIntegral(self)
- @property
- def denominator(self):
- return DummyIntegral(1)
- class HashTest(unittest.TestCase):
- def check_equal_hash(self, x, y):
- # check both that x and y are equal and that their hashes are equal
- self.assertEqual(hash(x), hash(y),
- "got different hashes for {!r} and {!r}".format(x, y))
- self.assertEqual(x, y)
- def test_bools(self):
- self.check_equal_hash(False, 0)
- self.check_equal_hash(True, 1)
- def test_integers(self):
- # check that equal values hash equal
- # exact integers
- for i in range(-1000, 1000):
- self.check_equal_hash(i, float(i))
- self.check_equal_hash(i, D(i))
- self.check_equal_hash(i, F(i))
- # the current hash is based on reduction modulo 2**n-1 for some
- # n, so pay special attention to numbers of the form 2**n and 2**n-1.
- for i in range(100):
- n = 2**i - 1
- if n == int(float(n)):
- self.check_equal_hash(n, float(n))
- self.check_equal_hash(-n, -float(n))
- self.check_equal_hash(n, D(n))
- self.check_equal_hash(n, F(n))
- self.check_equal_hash(-n, D(-n))
- self.check_equal_hash(-n, F(-n))
- n = 2**i
- self.check_equal_hash(n, float(n))
- self.check_equal_hash(-n, -float(n))
- self.check_equal_hash(n, D(n))
- self.check_equal_hash(n, F(n))
- self.check_equal_hash(-n, D(-n))
- self.check_equal_hash(-n, F(-n))
- # random values of various sizes
- for _ in range(1000):
- e = random.randrange(300)
- n = random.randrange(-10**e, 10**e)
- self.check_equal_hash(n, D(n))
- self.check_equal_hash(n, F(n))
- if n == int(float(n)):
- self.check_equal_hash(n, float(n))
- def test_binary_floats(self):
- # check that floats hash equal to corresponding Fractions and Decimals
- # floats that are distinct but numerically equal should hash the same
- self.check_equal_hash(0.0, -0.0)
- # zeros
- self.check_equal_hash(0.0, D(0))
- self.check_equal_hash(-0.0, D(0))
- self.check_equal_hash(-0.0, D('-0.0'))
- self.check_equal_hash(0.0, F(0))
- # infinities and nans
- self.check_equal_hash(float('inf'), D('inf'))
- self.check_equal_hash(float('-inf'), D('-inf'))
- for _ in range(1000):
- x = random.random() * math.exp(random.random()*200.0 - 100.0)
- self.check_equal_hash(x, D.from_float(x))
- self.check_equal_hash(x, F.from_float(x))
- def test_complex(self):
- # complex numbers with zero imaginary part should hash equal to
- # the corresponding float
- test_values = [0.0, -0.0, 1.0, -1.0, 0.40625, -5136.5,
- float('inf'), float('-inf')]
- for zero in -0.0, 0.0:
- for value in test_values:
- self.check_equal_hash(value, complex(value, zero))
- def test_decimals(self):
- # check that Decimal instances that have different representations
- # but equal values give the same hash
- zeros = ['0', '-0', '0.0', '-0.0e10', '000e-10']
- for zero in zeros:
- self.check_equal_hash(D(zero), D(0))
- self.check_equal_hash(D('1.00'), D(1))
- self.check_equal_hash(D('1.00000'), D(1))
- self.check_equal_hash(D('-1.00'), D(-1))
- self.check_equal_hash(D('-1.00000'), D(-1))
- self.check_equal_hash(D('123e2'), D(12300))
- self.check_equal_hash(D('1230e1'), D(12300))
- self.check_equal_hash(D('12300'), D(12300))
- self.check_equal_hash(D('12300.0'), D(12300))
- self.check_equal_hash(D('12300.00'), D(12300))
- self.check_equal_hash(D('12300.000'), D(12300))
- def test_fractions(self):
- # check special case for fractions where either the numerator
- # or the denominator is a multiple of _PyHASH_MODULUS
- self.assertEqual(hash(F(1, _PyHASH_MODULUS)), _PyHASH_INF)
- self.assertEqual(hash(F(-1, 3*_PyHASH_MODULUS)), -_PyHASH_INF)
- self.assertEqual(hash(F(7*_PyHASH_MODULUS, 1)), 0)
- self.assertEqual(hash(F(-_PyHASH_MODULUS, 1)), 0)
- # The numbers ABC doesn't enforce that the "true" division
- # of integers produces a float. This tests that the
- # Rational.__float__() method has required type conversions.
- x = F(DummyIntegral(1), DummyIntegral(2), _normalize=False)
- self.assertRaises(TypeError, lambda: x.numerator/x.denominator)
- self.assertEqual(float(x), 0.5)
- def test_hash_normalization(self):
- # Test for a bug encountered while changing long_hash.
- #
- # Given objects x and y, it should be possible for y's
- # __hash__ method to return hash(x) in order to ensure that
- # hash(x) == hash(y). But hash(x) is not exactly equal to the
- # result of x.__hash__(): there's some internal normalization
- # to make sure that the result fits in a C long, and is not
- # equal to the invalid hash value -1. This internal
- # normalization must therefore not change the result of
- # hash(x) for any x.
- class HalibutProxy:
- def __hash__(self):
- return hash('halibut')
- def __eq__(self, other):
- return other == 'halibut'
- x = {'halibut', HalibutProxy()}
- self.assertEqual(len(x), 1)
- class ComparisonTest(unittest.TestCase):
- def test_mixed_comparisons(self):
- # ordered list of distinct test values of various types:
- # int, float, Fraction, Decimal
- test_values = [
- float('-inf'),
- D('-1e425000000'),
- -1e308,
- F(-22, 7),
- -3.14,
- -2,
- 0.0,
- 1e-320,
- True,
- F('1.2'),
- D('1.3'),
- float('1.4'),
- F(275807, 195025),
- D('1.414213562373095048801688724'),
- F(114243, 80782),
- F(473596569, 84615),
- 7e200,
- D('infinity'),
- ]
- for i, first in enumerate(test_values):
- for second in test_values[i+1:]:
- self.assertLess(first, second)
- self.assertLessEqual(first, second)
- self.assertGreater(second, first)
- self.assertGreaterEqual(second, first)
- def test_complex(self):
- # comparisons with complex are special: equality and inequality
- # comparisons should always succeed, but order comparisons should
- # raise TypeError.
- z = 1.0 + 0j
- w = -3.14 + 2.7j
- for v in 1, 1.0, F(1), D(1), complex(1):
- self.assertEqual(z, v)
- self.assertEqual(v, z)
- for v in 2, 2.0, F(2), D(2), complex(2):
- self.assertNotEqual(z, v)
- self.assertNotEqual(v, z)
- self.assertNotEqual(w, v)
- self.assertNotEqual(v, w)
- for v in (1, 1.0, F(1), D(1), complex(1),
- 2, 2.0, F(2), D(2), complex(2), w):
- for op in operator.le, operator.lt, operator.ge, operator.gt:
- self.assertRaises(TypeError, op, z, v)
- self.assertRaises(TypeError, op, v, z)
- if __name__ == '__main__':
- unittest.main()
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