# test the invariant that
#   iff a==b then hash(a)==hash(b)
#

import os
import sys
import struct
import datetime
import unittest
import subprocess
 
from test import test_support

IS_64BIT = (struct.calcsize('l') == 8)

class HashEqualityTestCase(unittest.TestCase):

    def same_hash(self, *objlist):
        # Hash each object given and fail if
        # the hash values are not all the same.
        hashed = map(hash, objlist)
        for h in hashed[1:]:
            if h != hashed[0]:
                self.fail("hashed values differ: %r" % (objlist,))

    def test_numeric_literals(self):
        self.same_hash(1, 1L, 1.0, 1.0+0.0j)

    def test_coerced_integers(self):
        self.same_hash(int(1), long(1), float(1), complex(1),
                       int('1'), float('1.0'))

    def test_coerced_floats(self):
        self.same_hash(long(1.23e300), float(1.23e300))
        self.same_hash(float(0.5), complex(0.5, 0.0))

class HashRandomizationTests(unittest.TestCase):

    # Each subclass should define a field "repr_", containing the repr() of
    # an object to be tested

    def get_hash_command(self, repr_):
        return 'print(hash(%s))' % repr_

    def get_hash(self, repr_, seed=None):
        env = os.environ.copy()
        if seed is not None:
            env['PYTHONHASHSEED'] = str(seed)
        else:
            env.pop('PYTHONHASHSEED', None)
        cmd_line = [sys.executable, '-c', self.get_hash_command(repr_)]
        p = subprocess.Popen(cmd_line, stdin=subprocess.PIPE,
                             stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
                             env=env)
        out, err = p.communicate()
        out = test_support.strip_python_stderr(out)
        return int(out.strip())

    def test_randomized_hash(self):
        # two runs should return different hashes
        run1 = self.get_hash(self.repr_, seed='random')
        run2 = self.get_hash(self.repr_, seed='random')
        self.assertNotEqual(run1, run2)

class StringlikeHashRandomizationTests(HashRandomizationTests):
    def test_null_hash(self):
        # PYTHONHASHSEED=0 disables the randomized hash
        if IS_64BIT:
            known_hash_of_obj = 1453079729188098211
        else:
            known_hash_of_obj = -1600925533

        # Randomization is disabled by default:
        self.assertEqual(self.get_hash(self.repr_), known_hash_of_obj)

        # It can also be disabled by setting the seed to 0:
        self.assertEqual(self.get_hash(self.repr_, seed=0), known_hash_of_obj)

    def test_fixed_hash(self):
        # test a fixed seed for the randomized hash
        # Note that all types share the same values:
        if IS_64BIT:
            if sys.byteorder == 'little':
                h = -4410911502303878509
            else:
                h = -3570150969479994130
        else:
            if sys.byteorder == 'little':
                h = -206076799
            else:
                h = -1024014457
        self.assertEqual(self.get_hash(self.repr_, seed=42), h)

class StrHashRandomizationTests(StringlikeHashRandomizationTests):
    repr_ = repr('abc')

    def test_empty_string(self):
        self.assertEqual(hash(""), 0)

class UnicodeHashRandomizationTests(StringlikeHashRandomizationTests):
    repr_ = repr(u'abc')

    def test_empty_string(self):
        self.assertEqual(hash(u""), 0)

class BufferHashRandomizationTests(StringlikeHashRandomizationTests):
    repr_ = 'buffer("abc")'

    def test_empty_string(self):
        self.assertEqual(hash(buffer("")), 0)

class DatetimeTests(HashRandomizationTests):
    def get_hash_command(self, repr_):
        return 'import datetime; print(hash(%s))' % repr_

class DatetimeDateTests(DatetimeTests):
    repr_ = repr(datetime.date(1066, 10, 14))

class DatetimeDatetimeTests(DatetimeTests):
    repr_ = repr(datetime.datetime(1, 2, 3, 4, 5, 6, 7))

class DatetimeTimeTests(DatetimeTests):
    repr_ = repr(datetime.time(0))


def test_main():
    test_support.run_unittest(HashEqualityTestCase,
                              StrHashRandomizationTests,
                              UnicodeHashRandomizationTests,
                              BufferHashRandomizationTests,
                              DatetimeDateTests,
                              DatetimeDatetimeTests,
                              DatetimeTimeTests)


if __name__ == "__main__":
    test_main()