# 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 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) 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()