1# test interactions between int, float, Decimal and Fraction
2
3import unittest
4import random
5import math
6import sys
7import operator
8
9from decimal import Decimal as D
10from 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
18class DummyIntegral(int):
19    """Dummy Integral class to test conversion of the Rational to float."""
20
21    def __mul__(self, other):
22        return DummyIntegral(super().__mul__(other))
23    __rmul__ = __mul__
24
25    def __truediv__(self, other):
26        return NotImplemented
27    __rtruediv__ = __truediv__
28
29    @property
30    def numerator(self):
31        return DummyIntegral(self)
32
33    @property
34    def denominator(self):
35        return DummyIntegral(1)
36
37
38class HashTest(unittest.TestCase):
39    def check_equal_hash(self, x, y):
40        # check both that x and y are equal and that their hashes are equal
41        self.assertEqual(hash(x), hash(y),
42                         "got different hashes for {!r} and {!r}".format(x, y))
43        self.assertEqual(x, y)
44
45    def test_bools(self):
46        self.check_equal_hash(False, 0)
47        self.check_equal_hash(True, 1)
48
49    def test_integers(self):
50        # check that equal values hash equal
51
52        # exact integers
53        for i in range(-1000, 1000):
54            self.check_equal_hash(i, float(i))
55            self.check_equal_hash(i, D(i))
56            self.check_equal_hash(i, F(i))
57
58        # the current hash is based on reduction modulo 2**n-1 for some
59        # n, so pay special attention to numbers of the form 2**n and 2**n-1.
60        for i in range(100):
61            n = 2**i - 1
62            if n == int(float(n)):
63                self.check_equal_hash(n, float(n))
64                self.check_equal_hash(-n, -float(n))
65            self.check_equal_hash(n, D(n))
66            self.check_equal_hash(n, F(n))
67            self.check_equal_hash(-n, D(-n))
68            self.check_equal_hash(-n, F(-n))
69
70            n = 2**i
71            self.check_equal_hash(n, float(n))
72            self.check_equal_hash(-n, -float(n))
73            self.check_equal_hash(n, D(n))
74            self.check_equal_hash(n, F(n))
75            self.check_equal_hash(-n, D(-n))
76            self.check_equal_hash(-n, F(-n))
77
78        # random values of various sizes
79        for _ in range(1000):
80            e = random.randrange(300)
81            n = random.randrange(-10**e, 10**e)
82            self.check_equal_hash(n, D(n))
83            self.check_equal_hash(n, F(n))
84            if n == int(float(n)):
85                self.check_equal_hash(n, float(n))
86
87    def test_binary_floats(self):
88        # check that floats hash equal to corresponding Fractions and Decimals
89
90        # floats that are distinct but numerically equal should hash the same
91        self.check_equal_hash(0.0, -0.0)
92
93        # zeros
94        self.check_equal_hash(0.0, D(0))
95        self.check_equal_hash(-0.0, D(0))
96        self.check_equal_hash(-0.0, D('-0.0'))
97        self.check_equal_hash(0.0, F(0))
98
99        # infinities and nans
100        self.check_equal_hash(float('inf'), D('inf'))
101        self.check_equal_hash(float('-inf'), D('-inf'))
102
103        for _ in range(1000):
104            x = random.random() * math.exp(random.random()*200.0 - 100.0)
105            self.check_equal_hash(x, D.from_float(x))
106            self.check_equal_hash(x, F.from_float(x))
107
108    def test_complex(self):
109        # complex numbers with zero imaginary part should hash equal to
110        # the corresponding float
111
112        test_values = [0.0, -0.0, 1.0, -1.0, 0.40625, -5136.5,
113                       float('inf'), float('-inf')]
114
115        for zero in -0.0, 0.0:
116            for value in test_values:
117                self.check_equal_hash(value, complex(value, zero))
118
119    def test_decimals(self):
120        # check that Decimal instances that have different representations
121        # but equal values give the same hash
122        zeros = ['0', '-0', '0.0', '-0.0e10', '000e-10']
123        for zero in zeros:
124            self.check_equal_hash(D(zero), D(0))
125
126        self.check_equal_hash(D('1.00'), D(1))
127        self.check_equal_hash(D('1.00000'), D(1))
128        self.check_equal_hash(D('-1.00'), D(-1))
129        self.check_equal_hash(D('-1.00000'), D(-1))
130        self.check_equal_hash(D('123e2'), D(12300))
131        self.check_equal_hash(D('1230e1'), D(12300))
132        self.check_equal_hash(D('12300'), D(12300))
133        self.check_equal_hash(D('12300.0'), D(12300))
134        self.check_equal_hash(D('12300.00'), D(12300))
135        self.check_equal_hash(D('12300.000'), D(12300))
136
137    def test_fractions(self):
138        # check special case for fractions where either the numerator
139        # or the denominator is a multiple of _PyHASH_MODULUS
140        self.assertEqual(hash(F(1, _PyHASH_MODULUS)), _PyHASH_INF)
141        self.assertEqual(hash(F(-1, 3*_PyHASH_MODULUS)), -_PyHASH_INF)
142        self.assertEqual(hash(F(7*_PyHASH_MODULUS, 1)), 0)
143        self.assertEqual(hash(F(-_PyHASH_MODULUS, 1)), 0)
144
145        # The numbers ABC doesn't enforce that the "true" division
146        # of integers produces a float.  This tests that the
147        # Rational.__float__() method has required type conversions.
148        x = F(DummyIntegral(1), DummyIntegral(2), _normalize=False)
149        self.assertRaises(TypeError, lambda: x.numerator/x.denominator)
150        self.assertEqual(float(x), 0.5)
151
152    def test_hash_normalization(self):
153        # Test for a bug encountered while changing long_hash.
154        #
155        # Given objects x and y, it should be possible for y's
156        # __hash__ method to return hash(x) in order to ensure that
157        # hash(x) == hash(y).  But hash(x) is not exactly equal to the
158        # result of x.__hash__(): there's some internal normalization
159        # to make sure that the result fits in a C long, and is not
160        # equal to the invalid hash value -1.  This internal
161        # normalization must therefore not change the result of
162        # hash(x) for any x.
163
164        class HalibutProxy:
165            def __hash__(self):
166                return hash('halibut')
167            def __eq__(self, other):
168                return other == 'halibut'
169
170        x = {'halibut', HalibutProxy()}
171        self.assertEqual(len(x), 1)
172
173class ComparisonTest(unittest.TestCase):
174    def test_mixed_comparisons(self):
175
176        # ordered list of distinct test values of various types:
177        # int, float, Fraction, Decimal
178        test_values = [
179            float('-inf'),
180            D('-1e425000000'),
181            -1e308,
182            F(-22, 7),
183            -3.14,
184            -2,
185            0.0,
186            1e-320,
187            True,
188            F('1.2'),
189            D('1.3'),
190            float('1.4'),
191            F(275807, 195025),
192            D('1.414213562373095048801688724'),
193            F(114243, 80782),
194            F(473596569, 84615),
195            7e200,
196            D('infinity'),
197            ]
198        for i, first in enumerate(test_values):
199            for second in test_values[i+1:]:
200                self.assertLess(first, second)
201                self.assertLessEqual(first, second)
202                self.assertGreater(second, first)
203                self.assertGreaterEqual(second, first)
204
205    def test_complex(self):
206        # comparisons with complex are special:  equality and inequality
207        # comparisons should always succeed, but order comparisons should
208        # raise TypeError.
209        z = 1.0 + 0j
210        w = -3.14 + 2.7j
211
212        for v in 1, 1.0, F(1), D(1), complex(1):
213            self.assertEqual(z, v)
214            self.assertEqual(v, z)
215
216        for v in 2, 2.0, F(2), D(2), complex(2):
217            self.assertNotEqual(z, v)
218            self.assertNotEqual(v, z)
219            self.assertNotEqual(w, v)
220            self.assertNotEqual(v, w)
221
222        for v in (1, 1.0, F(1), D(1), complex(1),
223                  2, 2.0, F(2), D(2), complex(2), w):
224            for op in operator.le, operator.lt, operator.ge, operator.gt:
225                self.assertRaises(TypeError, op, z, v)
226                self.assertRaises(TypeError, op, v, z)
227
228
229if __name__ == '__main__':
230    unittest.main()
231