1 # test interactions between int, float, Decimal and Fraction 2 3 import unittest 4 import random 5 import math 6 import sys 7 import operator 8 9 from decimal import Decimal as D 10 from fractions import Fraction as F 11 12 # Constants related to the hash implementation; hash(x) is based 13 # on the reduction of x modulo the prime _PyHASH_MODULUS. 14 _PyHASH_MODULUS = sys.hash_info.modulus 15 _PyHASH_INF = sys.hash_info.inf 16 17 class HashTest(unittest.TestCase): 18 def check_equal_hash(self, x, y): 19 # check both that x and y are equal and that their hashes are equal 20 self.assertEqual(hash(x), hash(y), 21 "got different hashes for {!r} and {!r}".format(x, y)) 22 self.assertEqual(x, y) 23 24 def test_bools(self): 25 self.check_equal_hash(False, 0) 26 self.check_equal_hash(True, 1) 27 28 def test_integers(self): 29 # check that equal values hash equal 30 31 # exact integers 32 for i in range(-1000, 1000): 33 self.check_equal_hash(i, float(i)) 34 self.check_equal_hash(i, D(i)) 35 self.check_equal_hash(i, F(i)) 36 37 # the current hash is based on reduction modulo 2**n-1 for some 38 # n, so pay special attention to numbers of the form 2**n and 2**n-1. 39 for i in range(100): 40 n = 2**i - 1 41 if n == int(float(n)): 42 self.check_equal_hash(n, float(n)) 43 self.check_equal_hash(-n, -float(n)) 44 self.check_equal_hash(n, D(n)) 45 self.check_equal_hash(n, F(n)) 46 self.check_equal_hash(-n, D(-n)) 47 self.check_equal_hash(-n, F(-n)) 48 49 n = 2**i 50 self.check_equal_hash(n, float(n)) 51 self.check_equal_hash(-n, -float(n)) 52 self.check_equal_hash(n, D(n)) 53 self.check_equal_hash(n, F(n)) 54 self.check_equal_hash(-n, D(-n)) 55 self.check_equal_hash(-n, F(-n)) 56 57 # random values of various sizes 58 for _ in range(1000): 59 e = random.randrange(300) 60 n = random.randrange(-10**e, 10**e) 61 self.check_equal_hash(n, D(n)) 62 self.check_equal_hash(n, F(n)) 63 if n == int(float(n)): 64 self.check_equal_hash(n, float(n)) 65 66 def test_binary_floats(self): 67 # check that floats hash equal to corresponding Fractions and Decimals 68 69 # floats that are distinct but numerically equal should hash the same 70 self.check_equal_hash(0.0, -0.0) 71 72 # zeros 73 self.check_equal_hash(0.0, D(0)) 74 self.check_equal_hash(-0.0, D(0)) 75 self.check_equal_hash(-0.0, D('-0.0')) 76 self.check_equal_hash(0.0, F(0)) 77 78 # infinities and nans 79 self.check_equal_hash(float('inf'), D('inf')) 80 self.check_equal_hash(float('-inf'), D('-inf')) 81 82 for _ in range(1000): 83 x = random.random() * math.exp(random.random()*200.0 - 100.0) 84 self.check_equal_hash(x, D.from_float(x)) 85 self.check_equal_hash(x, F.from_float(x)) 86 87 def test_complex(self): 88 # complex numbers with zero imaginary part should hash equal to 89 # the corresponding float 90 91 test_values = [0.0, -0.0, 1.0, -1.0, 0.40625, -5136.5, 92 float('inf'), float('-inf')] 93 94 for zero in -0.0, 0.0: 95 for value in test_values: 96 self.check_equal_hash(value, complex(value, zero)) 97 98 def test_decimals(self): 99 # check that Decimal instances that have different representations 100 # but equal values give the same hash 101 zeros = ['0', '-0', '0.0', '-0.0e10', '000e-10'] 102 for zero in zeros: 103 self.check_equal_hash(D(zero), D(0)) 104 105 self.check_equal_hash(D('1.00'), D(1)) 106 self.check_equal_hash(D('1.00000'), D(1)) 107 self.check_equal_hash(D('-1.00'), D(-1)) 108 self.check_equal_hash(D('-1.00000'), D(-1)) 109 self.check_equal_hash(D('123e2'), D(12300)) 110 self.check_equal_hash(D('1230e1'), D(12300)) 111 self.check_equal_hash(D('12300'), D(12300)) 112 self.check_equal_hash(D('12300.0'), D(12300)) 113 self.check_equal_hash(D('12300.00'), D(12300)) 114 self.check_equal_hash(D('12300.000'), D(12300)) 115 116 def test_fractions(self): 117 # check special case for fractions where either the numerator 118 # or the denominator is a multiple of _PyHASH_MODULUS 119 self.assertEqual(hash(F(1, _PyHASH_MODULUS)), _PyHASH_INF) 120 self.assertEqual(hash(F(-1, 3*_PyHASH_MODULUS)), -_PyHASH_INF) 121 self.assertEqual(hash(F(7*_PyHASH_MODULUS, 1)), 0) 122 self.assertEqual(hash(F(-_PyHASH_MODULUS, 1)), 0) 123 124 def test_hash_normalization(self): 125 # Test for a bug encountered while changing long_hash. 126 # 127 # Given objects x and y, it should be possible for y's 128 # __hash__ method to return hash(x) in order to ensure that 129 # hash(x) == hash(y). But hash(x) is not exactly equal to the 130 # result of x.__hash__(): there's some internal normalization 131 # to make sure that the result fits in a C long, and is not 132 # equal to the invalid hash value -1. This internal 133 # normalization must therefore not change the result of 134 # hash(x) for any x. 135 136 class HalibutProxy: 137 def __hash__(self): 138 return hash('halibut') 139 def __eq__(self, other): 140 return other == 'halibut' 141 142 x = {'halibut', HalibutProxy()} 143 self.assertEqual(len(x), 1) 144 145 class ComparisonTest(unittest.TestCase): 146 def test_mixed_comparisons(self): 147 148 # ordered list of distinct test values of various types: 149 # int, float, Fraction, Decimal 150 test_values = [ 151 float('-inf'), 152 D('-1e425000000'), 153 -1e308, 154 F(-22, 7), 155 -3.14, 156 -2, 157 0.0, 158 1e-320, 159 True, 160 F('1.2'), 161 D('1.3'), 162 float('1.4'), 163 F(275807, 195025), 164 D('1.414213562373095048801688724'), 165 F(114243, 80782), 166 F(473596569, 84615), 167 7e200, 168 D('infinity'), 169 ] 170 for i, first in enumerate(test_values): 171 for second in test_values[i+1:]: 172 self.assertLess(first, second) 173 self.assertLessEqual(first, second) 174 self.assertGreater(second, first) 175 self.assertGreaterEqual(second, first) 176 177 def test_complex(self): 178 # comparisons with complex are special: equality and inequality 179 # comparisons should always succeed, but order comparisons should 180 # raise TypeError. 181 z = 1.0 + 0j 182 w = -3.14 + 2.7j 183 184 for v in 1, 1.0, F(1), D(1), complex(1): 185 self.assertEqual(z, v) 186 self.assertEqual(v, z) 187 188 for v in 2, 2.0, F(2), D(2), complex(2): 189 self.assertNotEqual(z, v) 190 self.assertNotEqual(v, z) 191 self.assertNotEqual(w, v) 192 self.assertNotEqual(v, w) 193 194 for v in (1, 1.0, F(1), D(1), complex(1), 195 2, 2.0, F(2), D(2), complex(2), w): 196 for op in operator.le, operator.lt, operator.ge, operator.gt: 197 self.assertRaises(TypeError, op, z, v) 198 self.assertRaises(TypeError, op, v, z) 199 200 201 if __name__ == '__main__': 202 unittest.main() 203
