Lib/test/test_array.py

"""Test the arraymodule.
   Roger E. Masse
"""

import collections.abc
import unittest
from test import support
from test.support import os_helper
from test.support import _2G
import weakref
import pickle
import operator
import struct
import sys

import array
from array import _array_reconstructor as array_reconstructor

sizeof_wchar = array.array('u').itemsize


class ArraySubclass(array.array):
    pass

class ArraySubclassWithKwargs(array.array):
    def __init__(self, typecode, newarg=None):
        array.array.__init__(self)

typecodes = 'ubBhHiIlLfdqQ'

class MiscTest(unittest.TestCase):

    def test_array_is_sequence(self):
        self.assertIsInstance(array.array("B"), collections.abc.MutableSequence)
        self.assertIsInstance(array.array("B"), collections.abc.Reversible)

    def test_bad_constructor(self):
        self.assertRaises(TypeError, array.array)
        self.assertRaises(TypeError, array.array, spam=42)
        self.assertRaises(TypeError, array.array, 'xx')
        self.assertRaises(ValueError, array.array, 'x')

    @support.cpython_only
    def test_disallow_instantiation(self):
        # Ensure that the type disallows instantiation (bpo-43916)
        tp = type(iter(array.array('I')))
        self.assertRaises(TypeError, tp)

    @support.cpython_only
    def test_immutable(self):
        # bpo-43908: check that array.array is immutable
        with self.assertRaises(TypeError):
            array.array.foo = 1

    def test_empty(self):
        # Exercise code for handling zero-length arrays
        a = array.array('B')
        a[:] = a
        self.assertEqual(len(a), 0)
        self.assertEqual(len(a + a), 0)
        self.assertEqual(len(a * 3), 0)
        a += a
        self.assertEqual(len(a), 0)


# Machine format codes.
#
# Search for "enum machine_format_code" in Modules/arraymodule.c to get the
# authoritative values.
UNKNOWN_FORMAT = -1
UNSIGNED_INT8 = 0
SIGNED_INT8 = 1
UNSIGNED_INT16_LE = 2
UNSIGNED_INT16_BE = 3
SIGNED_INT16_LE = 4
SIGNED_INT16_BE = 5
UNSIGNED_INT32_LE = 6
UNSIGNED_INT32_BE = 7
SIGNED_INT32_LE = 8
SIGNED_INT32_BE = 9
UNSIGNED_INT64_LE = 10
UNSIGNED_INT64_BE = 11
SIGNED_INT64_LE = 12
SIGNED_INT64_BE = 13
IEEE_754_FLOAT_LE = 14
IEEE_754_FLOAT_BE = 15
IEEE_754_DOUBLE_LE = 16
IEEE_754_DOUBLE_BE = 17
UTF16_LE = 18
UTF16_BE = 19
UTF32_LE = 20
UTF32_BE = 21

class ArrayReconstructorTest(unittest.TestCase):

    def test_error(self):
        self.assertRaises(TypeError, array_reconstructor,
                          "", "b", 0, b"")
        self.assertRaises(TypeError, array_reconstructor,
                          str, "b", 0, b"")
        self.assertRaises(TypeError, array_reconstructor,
                          array.array, "b", '', b"")
        self.assertRaises(TypeError, array_reconstructor,
                          array.array, "b", 0, "")
        self.assertRaises(ValueError, array_reconstructor,
                          array.array, "?", 0, b"")
        self.assertRaises(ValueError, array_reconstructor,
                          array.array, "b", UNKNOWN_FORMAT, b"")
        self.assertRaises(ValueError, array_reconstructor,
                          array.array, "b", 22, b"")
        self.assertRaises(ValueError, array_reconstructor,
                          array.array, "d", 16, b"a")

    def test_numbers(self):
        testcases = (
            (['B', 'H', 'I', 'L'], UNSIGNED_INT8, '=BBBB',
             [0x80, 0x7f, 0, 0xff]),
            (['b', 'h', 'i', 'l'], SIGNED_INT8, '=bbb',
             [-0x80, 0x7f, 0]),
            (['H', 'I', 'L'], UNSIGNED_INT16_LE, '<HHHH',
             [0x8000, 0x7fff, 0, 0xffff]),
            (['H', 'I', 'L'], UNSIGNED_INT16_BE, '>HHHH',
             [0x8000, 0x7fff, 0, 0xffff]),
            (['h', 'i', 'l'], SIGNED_INT16_LE, '<hhh',
             [-0x8000, 0x7fff, 0]),
            (['h', 'i', 'l'], SIGNED_INT16_BE, '>hhh',
             [-0x8000, 0x7fff, 0]),
            (['I', 'L'], UNSIGNED_INT32_LE, '<IIII',
             [1<<31, (1<<31)-1, 0, (1<<32)-1]),
            (['I', 'L'], UNSIGNED_INT32_BE, '>IIII',
             [1<<31, (1<<31)-1, 0, (1<<32)-1]),
            (['i', 'l'], SIGNED_INT32_LE, '<iii',
             [-1<<31, (1<<31)-1, 0]),
            (['i', 'l'], SIGNED_INT32_BE, '>iii',
             [-1<<31, (1<<31)-1, 0]),
            (['L'], UNSIGNED_INT64_LE, '<QQQQ',
             [1<<31, (1<<31)-1, 0, (1<<32)-1]),
            (['L'], UNSIGNED_INT64_BE, '>QQQQ',
             [1<<31, (1<<31)-1, 0, (1<<32)-1]),
            (['l'], SIGNED_INT64_LE, '<qqq',
             [-1<<31, (1<<31)-1, 0]),
            (['l'], SIGNED_INT64_BE, '>qqq',
             [-1<<31, (1<<31)-1, 0]),
            # The following tests for INT64 will raise an OverflowError
            # when run on a 32-bit machine. The tests are simply skipped
            # in that case.
            (['L'], UNSIGNED_INT64_LE, '<QQQQ',
             [1<<63, (1<<63)-1, 0, (1<<64)-1]),
            (['L'], UNSIGNED_INT64_BE, '>QQQQ',
             [1<<63, (1<<63)-1, 0, (1<<64)-1]),
            (['l'], SIGNED_INT64_LE, '<qqq',
             [-1<<63, (1<<63)-1, 0]),
            (['l'], SIGNED_INT64_BE, '>qqq',
             [-1<<63, (1<<63)-1, 0]),
            (['f'], IEEE_754_FLOAT_LE, '<ffff',
             [16711938.0, float('inf'), float('-inf'), -0.0]),
            (['f'], IEEE_754_FLOAT_BE, '>ffff',
             [16711938.0, float('inf'), float('-inf'), -0.0]),
            (['d'], IEEE_754_DOUBLE_LE, '<dddd',
             [9006104071832581.0, float('inf'), float('-inf'), -0.0]),
            (['d'], IEEE_754_DOUBLE_BE, '>dddd',
             [9006104071832581.0, float('inf'), float('-inf'), -0.0])
        )
        for testcase in testcases:
            valid_typecodes, mformat_code, struct_fmt, values = testcase
            arraystr = struct.pack(struct_fmt, *values)
            for typecode in valid_typecodes:
                try:
                    a = array.array(typecode, values)
                except OverflowError:
                    continue  # Skip this test case.
                b = array_reconstructor(
                    array.array, typecode, mformat_code, arraystr)
                self.assertEqual(a, b,
                    msg="{0!r} != {1!r}; testcase={2!r}".format(a, b, testcase))

    def test_unicode(self):
        teststr = "Bonne Journ\xe9e \U0002030a\U00020347"
        testcases = (
            (UTF16_LE, "UTF-16-LE"),
            (UTF16_BE, "UTF-16-BE"),
            (UTF32_LE, "UTF-32-LE"),
            (UTF32_BE, "UTF-32-BE")
        )
        for testcase in testcases:
            mformat_code, encoding = testcase
            a = array.array('u', teststr)
            b = array_reconstructor(
                array.array, 'u', mformat_code, teststr.encode(encoding))
            self.assertEqual(a, b,
                msg="{0!r} != {1!r}; testcase={2!r}".format(a, b, testcase))


class BaseTest:
    # Required class attributes (provided by subclasses
    # typecode: the typecode to test
    # example: an initializer usable in the constructor for this type
    # smallerexample: the same length as example, but smaller
    # biggerexample: the same length as example, but bigger
    # outside: An entry that is not in example
    # minitemsize: the minimum guaranteed itemsize

    def assertEntryEqual(self, entry1, entry2):
        self.assertEqual(entry1, entry2)

    def badtypecode(self):
        # Return a typecode that is different from our own
        return typecodes[(typecodes.index(self.typecode)+1) % len(typecodes)]

    def test_constructor(self):
        a = array.array(self.typecode)
        self.assertEqual(a.typecode, self.typecode)
        self.assertGreaterEqual(a.itemsize, self.minitemsize)
        self.assertRaises(TypeError, array.array, self.typecode, None)

    def test_len(self):
        a = array.array(self.typecode)
        a.append(self.example[0])
        self.assertEqual(len(a), 1)

        a = array.array(self.typecode, self.example)
        self.assertEqual(len(a), len(self.example))

    def test_buffer_info(self):
        a = array.array(self.typecode, self.example)
        self.assertRaises(TypeError, a.buffer_info, 42)
        bi = a.buffer_info()
        self.assertIsInstance(bi, tuple)
        self.assertEqual(len(bi), 2)
        self.assertIsInstance(bi[0], int)
        self.assertIsInstance(bi[1], int)
        self.assertEqual(bi[1], len(a))

    def test_byteswap(self):
        if self.typecode == 'u':
            example = '\U00100100'
        else:
            example = self.example
        a = array.array(self.typecode, example)
        self.assertRaises(TypeError, a.byteswap, 42)
        if a.itemsize in (1, 2, 4, 8):
            b = array.array(self.typecode, example)
            b.byteswap()
            if a.itemsize==1:
                self.assertEqual(a, b)
            else:
                self.assertNotEqual(a, b)
            b.byteswap()
            self.assertEqual(a, b)

    def test_copy(self):
        import copy
        a = array.array(self.typecode, self.example)
        b = copy.copy(a)
        self.assertNotEqual(id(a), id(b))
        self.assertEqual(a, b)

    def test_deepcopy(self):
        import copy
        a = array.array(self.typecode, self.example)
        b = copy.deepcopy(a)
        self.assertNotEqual(id(a), id(b))
        self.assertEqual(a, b)

    def test_reduce_ex(self):
        a = array.array(self.typecode, self.example)
        for protocol in range(3):
            self.assertIs(a.__reduce_ex__(protocol)[0], array.array)
        for protocol in range(3, pickle.HIGHEST_PROTOCOL + 1):
            self.assertIs(a.__reduce_ex__(protocol)[0], array_reconstructor)

    def test_pickle(self):
        for protocol in range(pickle.HIGHEST_PROTOCOL + 1):
            a = array.array(self.typecode, self.example)
            b = pickle.loads(pickle.dumps(a, protocol))
            self.assertNotEqual(id(a), id(b))
            self.assertEqual(a, b)

            a = ArraySubclass(self.typecode, self.example)
            a.x = 10
            b = pickle.loads(pickle.dumps(a, protocol))
            self.assertNotEqual(id(a), id(b))
            self.assertEqual(a, b)
            self.assertEqual(a.x, b.x)
            self.assertEqual(type(a), type(b))

    def test_pickle_for_empty_array(self):
        for protocol in range(pickle.HIGHEST_PROTOCOL + 1):
            a = array.array(self.typecode)
            b = pickle.loads(pickle.dumps(a, protocol))
            self.assertNotEqual(id(a), id(b))
            self.assertEqual(a, b)

            a = ArraySubclass(self.typecode)
            a.x = 10
            b = pickle.loads(pickle.dumps(a, protocol))
            self.assertNotEqual(id(a), id(b))
            self.assertEqual(a, b)
            self.assertEqual(a.x, b.x)
            self.assertEqual(type(a), type(b))

    def test_iterator_pickle(self):
        orig = array.array(self.typecode, self.example)
        data = list(orig)
        data2 = data[::-1]
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            # initial iterator
            itorig = iter(orig)
            d = pickle.dumps((itorig, orig), proto)
            it, a = pickle.loads(d)
            a.fromlist(data2)
            self.assertEqual(type(it), type(itorig))
            self.assertEqual(list(it), data + data2)

            # running iterator
            next(itorig)
            d = pickle.dumps((itorig, orig), proto)
            it, a = pickle.loads(d)
            a.fromlist(data2)
            self.assertEqual(type(it), type(itorig))
            self.assertEqual(list(it), data[1:] + data2)

            # empty iterator
            for i in range(1, len(data)):
                next(itorig)
            d = pickle.dumps((itorig, orig), proto)
            it, a = pickle.loads(d)
            a.fromlist(data2)
            self.assertEqual(type(it), type(itorig))
            self.assertEqual(list(it), data2)

            # exhausted iterator
            self.assertRaises(StopIteration, next, itorig)
            d = pickle.dumps((itorig, orig), proto)
            it, a = pickle.loads(d)
            a.fromlist(data2)
            self.assertEqual(list(it), [])

    def test_exhausted_iterator(self):
        a = array.array(self.typecode, self.example)
        self.assertEqual(list(a), list(self.example))
        exhit = iter(a)
        empit = iter(a)
        for x in exhit:  # exhaust the iterator
            next(empit)  # not exhausted
        a.append(self.outside)
        self.assertEqual(list(exhit), [])
        self.assertEqual(list(empit), [self.outside])
        self.assertEqual(list(a), list(self.example) + [self.outside])

    def test_reverse_iterator(self):
        a = array.array(self.typecode, self.example)
        self.assertEqual(list(a), list(self.example))
        self.assertEqual(list(reversed(a)), list(iter(a))[::-1])

    def test_reverse_iterator_picking(self):
        orig = array.array(self.typecode, self.example)
        data = list(orig)
        data2 = [self.outside] + data
        rev_data = data[len(data)-2::-1] + [self.outside]
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            # initial iterator
            itorig = reversed(orig)
            d = pickle.dumps((itorig, orig), proto)
            it, a = pickle.loads(d)
            a.insert(0, self.outside)
            self.assertEqual(type(it), type(itorig))
            self.assertEqual(list(it), rev_data)
            self.assertEqual(list(a), data2)

            # running iterator
            next(itorig)
            d = pickle.dumps((itorig, orig), proto)
            it, a = pickle.loads(d)
            a.insert(0, self.outside)
            self.assertEqual(type(it), type(itorig))
            self.assertEqual(list(it), rev_data[1:])
            self.assertEqual(list(a), data2)

            # empty iterator
            for i in range(1, len(data)):
                next(itorig)
            d = pickle.dumps((itorig, orig), proto)
            it, a = pickle.loads(d)
            a.insert(0, self.outside)
            self.assertEqual(type(it), type(itorig))
            self.assertEqual(list(it), [])
            self.assertEqual(list(a), data2)

            # exhausted iterator
            self.assertRaises(StopIteration, next, itorig)
            d = pickle.dumps((itorig, orig), proto)
            it, a = pickle.loads(d)
            a.insert(0, self.outside)
            self.assertEqual(list(it), [])
            self.assertEqual(list(a), data2)

    def test_exhausted_reverse_iterator(self):
        a = array.array(self.typecode, self.example)
        self.assertEqual(list(a), list(self.example))
        exhit = reversed(a)
        empit = reversed(a)
        for x in exhit:  # exhaust the iterator
            next(empit)  # Pointing past the 0th position.
        a.insert(0, self.outside)
        self.assertEqual(list(exhit), [])
        # The iterator index points past the 0th position so inserting
        # an element in the beginning does not make it appear.
        self.assertEqual(list(empit), [])
        self.assertEqual(list(a), [self.outside] + list(self.example))

    def test_insert(self):
        a = array.array(self.typecode, self.example)
        a.insert(0, self.example[0])
        self.assertEqual(len(a), 1+len(self.example))
        self.assertEqual(a[0], a[1])
        self.assertRaises(TypeError, a.insert)
        self.assertRaises(TypeError, a.insert, None)
        self.assertRaises(TypeError, a.insert, 0, None)

        a = array.array(self.typecode, self.example)
        a.insert(-1, self.example[0])
        self.assertEqual(
            a,
            array.array(
                self.typecode,
                self.example[:-1] + self.example[:1] + self.example[-1:]
            )
        )

        a = array.array(self.typecode, self.example)
        a.insert(-1000, self.example[0])
        self.assertEqual(
            a,
            array.array(self.typecode, self.example[:1] + self.example)
        )

        a = array.array(self.typecode, self.example)
        a.insert(1000, self.example[0])
        self.assertEqual(
            a,
            array.array(self.typecode, self.example + self.example[:1])
        )

    def test_tofromfile(self):
        a = array.array(self.typecode, 2*self.example)
        self.assertRaises(TypeError, a.tofile)
        os_helper.unlink(os_helper.TESTFN)
        f = open(os_helper.TESTFN, 'wb')
        try:
            a.tofile(f)
            f.close()
            b = array.array(self.typecode)
            f = open(os_helper.TESTFN, 'rb')
            self.assertRaises(TypeError, b.fromfile)
            b.fromfile(f, len(self.example))
            self.assertEqual(b, array.array(self.typecode, self.example))
            self.assertNotEqual(a, b)
            self.assertRaises(EOFError, b.fromfile, f, len(self.example)+1)
            self.assertEqual(a, b)
            f.close()
        finally:
            if not f.closed:
                f.close()
            os_helper.unlink(os_helper.TESTFN)

    def test_fromfile_ioerror(self):
        # Issue #5395: Check if fromfile raises a proper OSError
        # instead of EOFError.
        a = array.array(self.typecode)
        f = open(os_helper.TESTFN, 'wb')
        try:
            self.assertRaises(OSError, a.fromfile, f, len(self.example))
        finally:
            f.close()
            os_helper.unlink(os_helper.TESTFN)

    def test_filewrite(self):
        a = array.array(self.typecode, 2*self.example)
        f = open(os_helper.TESTFN, 'wb')
        try:
            f.write(a)
            f.close()
            b = array.array(self.typecode)
            f = open(os_helper.TESTFN, 'rb')
            b.fromfile(f, len(self.example))
            self.assertEqual(b, array.array(self.typecode, self.example))
            self.assertNotEqual(a, b)
            b.fromfile(f, len(self.example))
            self.assertEqual(a, b)
            f.close()
        finally:
            if not f.closed:
                f.close()
            os_helper.unlink(os_helper.TESTFN)

    def test_tofromlist(self):
        a = array.array(self.typecode, 2*self.example)
        b = array.array(self.typecode)
        self.assertRaises(TypeError, a.tolist, 42)
        self.assertRaises(TypeError, b.fromlist)
        self.assertRaises(TypeError, b.fromlist, 42)
        self.assertRaises(TypeError, b.fromlist, [None])
        b.fromlist(a.tolist())
        self.assertEqual(a, b)

    def test_tofrombytes(self):
        a = array.array(self.typecode, 2*self.example)
        b = array.array(self.typecode)
        self.assertRaises(TypeError, a.tobytes, 42)
        self.assertRaises(TypeError, b.frombytes)
        self.assertRaises(TypeError, b.frombytes, 42)
        b.frombytes(a.tobytes())
        c = array.array(self.typecode, bytearray(a.tobytes()))
        self.assertEqual(a, b)
        self.assertEqual(a, c)
        if a.itemsize>1:
            self.assertRaises(ValueError, b.frombytes, b"x")

    def test_fromarray(self):
        a = array.array(self.typecode, self.example)
        b = array.array(self.typecode, a)
        self.assertEqual(a, b)

    def test_repr(self):
        a = array.array(self.typecode, 2*self.example)
        self.assertEqual(a, eval(repr(a), {"array": array.array}))

        a = array.array(self.typecode)
        self.assertEqual(repr(a), "array('%s')" % self.typecode)

    def test_str(self):
        a = array.array(self.typecode, 2*self.example)
        str(a)

    def test_cmp(self):
        a = array.array(self.typecode, self.example)
        self.assertIs(a == 42, False)
        self.assertIs(a != 42, True)

        self.assertIs(a == a, True)
        self.assertIs(a != a, False)
        self.assertIs(a < a, False)
        self.assertIs(a <= a, True)
        self.assertIs(a > a, False)
        self.assertIs(a >= a, True)

        al = array.array(self.typecode, self.smallerexample)
        ab = array.array(self.typecode, self.biggerexample)

        self.assertIs(a == 2*a, False)
        self.assertIs(a != 2*a, True)
        self.assertIs(a < 2*a, True)
        self.assertIs(a <= 2*a, True)
        self.assertIs(a > 2*a, False)
        self.assertIs(a >= 2*a, False)

        self.assertIs(a == al, False)
        self.assertIs(a != al, True)
        self.assertIs(a < al, False)
        self.assertIs(a <= al, False)
        self.assertIs(a > al, True)
        self.assertIs(a >= al, True)

        self.assertIs(a == ab, False)
        self.assertIs(a != ab, True)
        self.assertIs(a < ab, True)
        self.assertIs(a <= ab, True)
        self.assertIs(a > ab, False)
        self.assertIs(a >= ab, False)

    def test_add(self):
        a = array.array(self.typecode, self.example) \
            + array.array(self.typecode, self.example[::-1])
        self.assertEqual(
            a,
            array.array(self.typecode, self.example + self.example[::-1])
        )

        b = array.array(self.badtypecode())
        self.assertRaises(TypeError, a.__add__, b)

        self.assertRaises(TypeError, a.__add__, "bad")

    def test_iadd(self):
        a = array.array(self.typecode, self.example[::-1])
        b = a
        a += array.array(self.typecode, 2*self.example)
        self.assertIs(a, b)
        self.assertEqual(
            a,
            array.array(self.typecode, self.example[::-1]+2*self.example)
        )
        a = array.array(self.typecode, self.example)
        a += a
        self.assertEqual(
            a,
            array.array(self.typecode, self.example + self.example)
        )

        b = array.array(self.badtypecode())
        self.assertRaises(TypeError, a.__add__, b)

        self.assertRaises(TypeError, a.__iadd__, "bad")

    def test_mul(self):
        a = 5*array.array(self.typecode, self.example)
        self.assertEqual(
            a,
            array.array(self.typecode, 5*self.example)
        )

        a = array.array(self.typecode, self.example)*5
        self.assertEqual(
            a,
            array.array(self.typecode, self.example*5)
        )

        a = 0*array.array(self.typecode, self.example)
        self.assertEqual(
            a,
            array.array(self.typecode)
        )

        a = (-1)*array.array(self.typecode, self.example)
        self.assertEqual(
            a,
            array.array(self.typecode)
        )

        a = 5 * array.array(self.typecode, self.example[:1])
        self.assertEqual(
            a,
            array.array(self.typecode, [a[0]] * 5)
        )

        self.assertRaises(TypeError, a.__mul__, "bad")

    def test_imul(self):
        a = array.array(self.typecode, self.example)
        b = a

        a *= 5
        self.assertIs(a, b)
        self.assertEqual(
            a,
            array.array(self.typecode, 5*self.example)
        )

        a *= 0
        self.assertIs(a, b)
        self.assertEqual(a, array.array(self.typecode))

        a *= 1000
        self.assertIs(a, b)
        self.assertEqual(a, array.array(self.typecode))

        a *= -1
        self.assertIs(a, b)
        self.assertEqual(a, array.array(self.typecode))

        a = array.array(self.typecode, self.example)
        a *= -1
        self.assertEqual(a, array.array(self.typecode))

        self.assertRaises(TypeError, a.__imul__, "bad")

    def test_getitem(self):
        a = array.array(self.typecode, self.example)
        self.assertEntryEqual(a[0], self.example[0])
        self.assertEntryEqual(a[0], self.example[0])
        self.assertEntryEqual(a[-1], self.example[-1])
        self.assertEntryEqual(a[-1], self.example[-1])
        self.assertEntryEqual(a[len(self.example)-1], self.example[-1])
        self.assertEntryEqual(a[-len(self.example)], self.example[0])
        self.assertRaises(TypeError, a.__getitem__)
        self.assertRaises(IndexError, a.__getitem__, len(self.example))
        self.assertRaises(IndexError, a.__getitem__, -len(self.example)-1)

    def test_setitem(self):
        a = array.array(self.typecode, self.example)
        a[0] = a[-1]
        self.assertEntryEqual(a[0], a[-1])

        a = array.array(self.typecode, self.example)
        a[0] = a[-1]
        self.assertEntryEqual(a[0], a[-1])

        a = array.array(self.typecode, self.example)
        a[-1] = a[0]
        self.assertEntryEqual(a[0], a[-1])

        a = array.array(self.typecode, self.example)
        a[-1] = a[0]
        self.assertEntryEqual(a[0], a[-1])

        a = array.array(self.typecode, self.example)
        a[len(self.example)-1] = a[0]
        self.assertEntryEqual(a[0], a[-1])

        a = array.array(self.typecode, self.example)
        a[-len(self.example)] = a[-1]
        self.assertEntryEqual(a[0], a[-1])

        self.assertRaises(TypeError, a.__setitem__)
        self.assertRaises(TypeError, a.__setitem__, None)
        self.assertRaises(TypeError, a.__setitem__, 0, None)
        self.assertRaises(
            IndexError,
            a.__setitem__,
            len(self.example), self.example[0]
        )
        self.assertRaises(
            IndexError,
            a.__setitem__,
            -len(self.example)-1, self.example[0]
        )

    def test_delitem(self):
        a = array.array(self.typecode, self.example)
        del a[0]
        self.assertEqual(
            a,
            array.array(self.typecode, self.example[1:])
        )

        a = array.array(self.typecode, self.example)
        del a[-1]
        self.assertEqual(
            a,
            array.array(self.typecode, self.example[:-1])
        )

        a = array.array(self.typecode, self.example)
        del a[len(self.example)-1]
        self.assertEqual(
            a,
            array.array(self.typecode, self.example[:-1])
        )

        a = array.array(self.typecode, self.example)
        del a[-len(self.example)]
        self.assertEqual(
            a,
            array.array(self.typecode, self.example[1:])
        )

        self.assertRaises(TypeError, a.__delitem__)
        self.assertRaises(TypeError, a.__delitem__, None)
        self.assertRaises(IndexError, a.__delitem__, len(self.example))
        self.assertRaises(IndexError, a.__delitem__, -len(self.example)-1)

    def test_getslice(self):
        a = array.array(self.typecode, self.example)
        self.assertEqual(a[:], a)

        self.assertEqual(
            a[1:],
            array.array(self.typecode, self.example[1:])
        )

        self.assertEqual(
            a[:1],
            array.array(self.typecode, self.example[:1])
        )

        self.assertEqual(
            a[:-1],
            array.array(self.typecode, self.example[:-1])
        )

        self.assertEqual(
            a[-1:],
            array.array(self.typecode, self.example[-1:])
        )

        self.assertEqual(
            a[-1:-1],
            array.array(self.typecode)
        )

        self.assertEqual(
            a[2:1],
            array.array(self.typecode)
        )

        self.assertEqual(
            a[1000:],
            array.array(self.typecode)
        )
        self.assertEqual(a[-1000:], a)
        self.assertEqual(a[:1000], a)
        self.assertEqual(
            a[:-1000],
            array.array(self.typecode)
        )
        self.assertEqual(a[-1000:1000], a)
        self.assertEqual(
            a[2000:1000],
            array.array(self.typecode)
        )

    def test_extended_getslice(self):
        # Test extended slicing by comparing with list slicing
        # (Assumes list conversion works correctly, too)
        a = array.array(self.typecode, self.example)
        indices = (0, None, 1, 3, 19, 100, sys.maxsize, -1, -2, -31, -100)
        for start in indices:
            for stop in indices:
                # Everything except the initial 0 (invalid step)
                for step in indices[1:]:
                    self.assertEqual(list(a[start:stop:step]),
                                     list(a)[start:stop:step])

    def test_setslice(self):
        a = array.array(self.typecode, self.example)
        a[:1] = a
        self.assertEqual(
            a,
            array.array(self.typecode, self.example + self.example[1:])
        )

        a = array.array(self.typecode, self.example)
        a[:-1] = a
        self.assertEqual(
            a,
            array.array(self.typecode, self.example + self.example[-1:])
        )

        a = array.array(self.typecode, self.example)
        a[-1:] = a
        self.assertEqual(
            a,
            array.array(self.typecode, self.example[:-1] + self.example)
        )

        a = array.array(self.typecode, self.example)
        a[1:] = a
        self.assertEqual(
            a,
            array.array(self.typecode, self.example[:1] + self.example)
        )

        a = array.array(self.typecode, self.example)
        a[1:-1] = a
        self.assertEqual(
            a,
            array.array(
                self.typecode,
                self.example[:1] + self.example + self.example[-1:]
            )
        )

        a = array.array(self.typecode, self.example)
        a[1000:] = a
        self.assertEqual(
            a,
            array.array(self.typecode, 2*self.example)
        )

        a = array.array(self.typecode, self.example)
        a[-1000:] = a
        self.assertEqual(
            a,
            array.array(self.typecode, self.example)
        )

        a = array.array(self.typecode, self.example)
        a[:1000] = a
        self.assertEqual(
            a,
            array.array(self.typecode, self.example)
        )

        a = array.array(self.typecode, self.example)
        a[:-1000] = a
        self.assertEqual(
            a,
            array.array(self.typecode, 2*self.example)
        )

        a = array.array(self.typecode, self.example)
        a[1:0] = a
        self.assertEqual(
            a,
            array.array(self.typecode, self.example[:1] + self.example + self.example[1:])
        )

        a = array.array(self.typecode, self.example)
        a[2000:1000] = a
        self.assertEqual(
            a,
            array.array(self.typecode, 2*self.example)
        )

        a = array.array(self.typecode, self.example)
        self.assertRaises(TypeError, a.__setitem__, slice(0, 0), None)
        self.assertRaises(TypeError, a.__setitem__, slice(0, 1), None)

        b = array.array(self.badtypecode())
        self.assertRaises(TypeError, a.__setitem__, slice(0, 0), b)
        self.assertRaises(TypeError, a.__setitem__, slice(0, 1), b)

    def test_extended_set_del_slice(self):
        indices = (0, None, 1, 3, 19, 100, sys.maxsize, -1, -2, -31, -100)
        for start in indices:
            for stop in indices:
                # Everything except the initial 0 (invalid step)
                for step in indices[1:]:
                    a = array.array(self.typecode, self.example)
                    L = list(a)
                    # Make sure we have a slice of exactly the right length,
                    # but with (hopefully) different data.
                    data = L[start:stop:step]
                    data.reverse()
                    L[start:stop:step] = data
                    a[start:stop:step] = array.array(self.typecode, data)
                    self.assertEqual(a, array.array(self.typecode, L))

                    del L[start:stop:step]
                    del a[start:stop:step]
                    self.assertEqual(a, array.array(self.typecode, L))

    def test_index(self):
        example = 2*self.example
        a = array.array(self.typecode, example)
        self.assertRaises(TypeError, a.index)
        for x in example:
            self.assertEqual(a.index(x), example.index(x))
        self.assertRaises(ValueError, a.index, None)
        self.assertRaises(ValueError, a.index, self.outside)

        a = array.array('i', [-2, -1, 0, 0, 1, 2])
        self.assertEqual(a.index(0), 2)
        self.assertEqual(a.index(0, 2), 2)
        self.assertEqual(a.index(0, -4), 2)
        self.assertEqual(a.index(-2, -10), 0)
        self.assertEqual(a.index(0, 3), 3)
        self.assertEqual(a.index(0, -3), 3)
        self.assertEqual(a.index(0, 3, 4), 3)
        self.assertEqual(a.index(0, -3, -2), 3)
        self.assertRaises(ValueError, a.index, 2, 0, -10)

    def test_count(self):
        example = 2*self.example
        a = array.array(self.typecode, example)
        self.assertRaises(TypeError, a.count)
        for x in example:
            self.assertEqual(a.count(x), example.count(x))
        self.assertEqual(a.count(self.outside), 0)
        self.assertEqual(a.count(None), 0)

    def test_remove(self):
        for x in self.example:
            example = 2*self.example
            a = array.array(self.typecode, example)
            pos = example.index(x)
            example2 = example[:pos] + example[pos+1:]
            a.remove(x)
            self.assertEqual(a, array.array(self.typecode, example2))

        a = array.array(self.typecode, self.example)
        self.assertRaises(ValueError, a.remove, self.outside)

        self.assertRaises(ValueError, a.remove, None)

    def test_pop(self):
        a = array.array(self.typecode)
        self.assertRaises(IndexError, a.pop)

        a = array.array(self.typecode, 2*self.example)
        self.assertRaises(TypeError, a.pop, 42, 42)
        self.assertRaises(TypeError, a.pop, None)
        self.assertRaises(IndexError, a.pop, len(a))
        self.assertRaises(IndexError, a.pop, -len(a)-1)

        self.assertEntryEqual(a.pop(0), self.example[0])
        self.assertEqual(
            a,
            array.array(self.typecode, self.example[1:]+self.example)
        )
        self.assertEntryEqual(a.pop(1), self.example[2])
        self.assertEqual(
            a,
            array.array(self.typecode, self.example[1:2]+self.example[3:]+self.example)
        )
        self.assertEntryEqual(a.pop(0), self.example[1])
        self.assertEntryEqual(a.pop(), self.example[-1])
        self.assertEqual(
            a,
            array.array(self.typecode, self.example[3:]+self.example[:-1])
        )

    def test_reverse(self):
        a = array.array(self.typecode, self.example)
        self.assertRaises(TypeError, a.reverse, 42)
        a.reverse()
        self.assertEqual(
            a,
            array.array(self.typecode, self.example[::-1])
        )

    def test_extend(self):
        a = array.array(self.typecode, self.example)
        self.assertRaises(TypeError, a.extend)
        a.extend(array.array(self.typecode, self.example[::-1]))
        self.assertEqual(
            a,
            array.array(self.typecode, self.example+self.example[::-1])
        )

        a = array.array(self.typecode, self.example)
        a.extend(a)
        self.assertEqual(
            a,
            array.array(self.typecode, self.example+self.example)
        )

        b = array.array(self.badtypecode())
        self.assertRaises(TypeError, a.extend, b)

        a = array.array(self.typecode, self.example)
        a.extend(self.example[::-1])
        self.assertEqual(
            a,
            array.array(self.typecode, self.example+self.example[::-1])
        )

    def test_constructor_with_iterable_argument(self):
        a = array.array(self.typecode, iter(self.example))
        b = array.array(self.typecode, self.example)
        self.assertEqual(a, b)

        # non-iterable argument
        self.assertRaises(TypeError, array.array, self.typecode, 10)

        # pass through errors raised in __iter__
        class A:
            def __iter__(self):
                raise UnicodeError
        self.assertRaises(UnicodeError, array.array, self.typecode, A())

        # pass through errors raised in next()
        def B():
            raise UnicodeError
            yield None
        self.assertRaises(UnicodeError, array.array, self.typecode, B())

    def test_coveritertraverse(self):
        try:
            import gc
        except ImportError:
            self.skipTest('gc module not available')
        a = array.array(self.typecode)
        l = [iter(a)]
        l.append(l)
        gc.collect()

    def test_buffer(self):
        a = array.array(self.typecode, self.example)
        m = memoryview(a)
        expected = m.tobytes()
        self.assertEqual(a.tobytes(), expected)
        self.assertEqual(a.tobytes()[0], expected[0])
        # Resizing is forbidden when there are buffer exports.
        # For issue 4509, we also check after each error that
        # the array was not modified.
        self.assertRaises(BufferError, a.append, a[0])
        self.assertEqual(m.tobytes(), expected)
        self.assertRaises(BufferError, a.extend, a[0:1])
        self.assertEqual(m.tobytes(), expected)
        self.assertRaises(BufferError, a.remove, a[0])
        self.assertEqual(m.tobytes(), expected)
        self.assertRaises(BufferError, a.pop, 0)
        self.assertEqual(m.tobytes(), expected)
        self.assertRaises(BufferError, a.fromlist, a.tolist())
        self.assertEqual(m.tobytes(), expected)
        self.assertRaises(BufferError, a.frombytes, a.tobytes())
        self.assertEqual(m.tobytes(), expected)
        if self.typecode == 'u':
            self.assertRaises(BufferError, a.fromunicode, a.tounicode())
            self.assertEqual(m.tobytes(), expected)
        self.assertRaises(BufferError, operator.imul, a, 2)
        self.assertEqual(m.tobytes(), expected)
        self.assertRaises(BufferError, operator.imul, a, 0)
        self.assertEqual(m.tobytes(), expected)
        self.assertRaises(BufferError, operator.setitem, a, slice(0, 0), a)
        self.assertEqual(m.tobytes(), expected)
        self.assertRaises(BufferError, operator.delitem, a, 0)
        self.assertEqual(m.tobytes(), expected)
        self.assertRaises(BufferError, operator.delitem, a, slice(0, 1))
        self.assertEqual(m.tobytes(), expected)

    def test_weakref(self):
        s = array.array(self.typecode, self.example)
        p = weakref.proxy(s)
        self.assertEqual(p.tobytes(), s.tobytes())
        s = None
        self.assertRaises(ReferenceError, len, p)

    @unittest.skipUnless(hasattr(sys, 'getrefcount'),
                         'test needs sys.getrefcount()')
    def test_bug_782369(self):
        for i in range(10):
            b = array.array('B', range(64))
        rc = sys.getrefcount(10)
        for i in range(10):
            b = array.array('B', range(64))
        self.assertEqual(rc, sys.getrefcount(10))

    def test_subclass_with_kwargs(self):
        # SF bug #1486663 -- this used to erroneously raise a TypeError
        ArraySubclassWithKwargs('b', newarg=1)

    def test_create_from_bytes(self):
        # XXX This test probably needs to be moved in a subclass or
        # generalized to use self.typecode.
        a = array.array('H', b"1234")
        self.assertEqual(len(a) * a.itemsize, 4)

    @support.cpython_only
    def test_sizeof_with_buffer(self):
        a = array.array(self.typecode, self.example)
        basesize = support.calcvobjsize('Pn2Pi')
        buffer_size = a.buffer_info()[1] * a.itemsize
        support.check_sizeof(self, a, basesize + buffer_size)

    @support.cpython_only
    def test_sizeof_without_buffer(self):
        a = array.array(self.typecode)
        basesize = support.calcvobjsize('Pn2Pi')
        support.check_sizeof(self, a, basesize)

    def test_initialize_with_unicode(self):
        if self.typecode != 'u':
            with self.assertRaises(TypeError) as cm:
                a = array.array(self.typecode, 'foo')
            self.assertIn("cannot use a str", str(cm.exception))
            with self.assertRaises(TypeError) as cm:
                a = array.array(self.typecode, array.array('u', 'foo'))
            self.assertIn("cannot use a unicode array", str(cm.exception))
        else:
            a = array.array(self.typecode, "foo")
            a = array.array(self.typecode, array.array('u', 'foo'))

    @support.cpython_only
    def test_obsolete_write_lock(self):
        from _testcapi import getbuffer_with_null_view
        a = array.array('B', b"")
        self.assertRaises(BufferError, getbuffer_with_null_view, a)

    def test_free_after_iterating(self):
        support.check_free_after_iterating(self, iter, array.array,
                                           (self.typecode,))
        support.check_free_after_iterating(self, reversed, array.array,
                                           (self.typecode,))

class StringTest(BaseTest):

    def test_setitem(self):
        super().test_setitem()
        a = array.array(self.typecode, self.example)
        self.assertRaises(TypeError, a.__setitem__, 0, self.example[:2])

class UnicodeTest(StringTest, unittest.TestCase):
    typecode = 'u'
    example = '\x01\u263a\x00\ufeff'
    smallerexample = '\x01\u263a\x00\ufefe'
    biggerexample = '\x01\u263a\x01\ufeff'
    outside = str('\x33')
    minitemsize = 2

    def test_unicode(self):
        self.assertRaises(TypeError, array.array, 'b', 'foo')

        a = array.array('u', '\xa0\xc2\u1234')
        a.fromunicode(' ')
        a.fromunicode('')
        a.fromunicode('')
        a.fromunicode('\x11abc\xff\u1234')
        s = a.tounicode()
        self.assertEqual(s, '\xa0\xc2\u1234 \x11abc\xff\u1234')
        self.assertEqual(a.itemsize, sizeof_wchar)

        s = '\x00="\'a\\b\x80\xff\u0000\u0001\u1234'
        a = array.array('u', s)
        self.assertEqual(
            repr(a),
            "array('u', '\\x00=\"\\'a\\\\b\\x80\xff\\x00\\x01\u1234')")

        self.assertRaises(TypeError, a.fromunicode)

    def test_issue17223(self):
        # this used to crash
        if sizeof_wchar == 4:
            # U+FFFFFFFF is an invalid code point in Unicode 6.0
            invalid_str = b'\xff\xff\xff\xff'
        else:
            # PyUnicode_FromUnicode() cannot fail with 16-bit wchar_t
            self.skipTest("specific to 32-bit wchar_t")
        a = array.array('u', invalid_str)
        self.assertRaises(ValueError, a.tounicode)
        self.assertRaises(ValueError, str, a)

class NumberTest(BaseTest):

    def test_extslice(self):
        a = array.array(self.typecode, range(5))
        self.assertEqual(a[::], a)
        self.assertEqual(a[::2], array.array(self.typecode, [0,2,4]))
        self.assertEqual(a[1::2], array.array(self.typecode, [1,3]))
        self.assertEqual(a[::-1], array.array(self.typecode, [4,3,2,1,0]))
        self.assertEqual(a[::-2], array.array(self.typecode, [4,2,0]))
        self.assertEqual(a[3::-2], array.array(self.typecode, [3,1]))
        self.assertEqual(a[-100:100:], a)
        self.assertEqual(a[100:-100:-1], a[::-1])
        self.assertEqual(a[-100:100:2], array.array(self.typecode, [0,2,4]))
        self.assertEqual(a[1000:2000:2], array.array(self.typecode, []))
        self.assertEqual(a[-1000:-2000:-2], array.array(self.typecode, []))

    def test_delslice(self):
        a = array.array(self.typecode, range(5))
        del a[::2]
        self.assertEqual(a, array.array(self.typecode, [1,3]))
        a = array.array(self.typecode, range(5))
        del a[1::2]
        self.assertEqual(a, array.array(self.typecode, [0,2,4]))
        a = array.array(self.typecode, range(5))
        del a[1::-2]
        self.assertEqual(a, array.array(self.typecode, [0,2,3,4]))
        a = array.array(self.typecode, range(10))
        del a[::1000]
        self.assertEqual(a, array.array(self.typecode, [1,2,3,4,5,6,7,8,9]))
        # test issue7788
        a = array.array(self.typecode, range(10))
        del a[9::1<<333]

    def test_assignment(self):
        a = array.array(self.typecode, range(10))
        a[::2] = array.array(self.typecode, [42]*5)
        self.assertEqual(a, array.array(self.typecode, [42, 1, 42, 3, 42, 5, 42, 7, 42, 9]))
        a = array.array(self.typecode, range(10))
        a[::-4] = array.array(self.typecode, [10]*3)
        self.assertEqual(a, array.array(self.typecode, [0, 10, 2, 3, 4, 10, 6, 7, 8 ,10]))
        a = array.array(self.typecode, range(4))
        a[::-1] = a
        self.assertEqual(a, array.array(self.typecode, [3, 2, 1, 0]))
        a = array.array(self.typecode, range(10))
        b = a[:]
        c = a[:]
        ins = array.array(self.typecode, range(2))
        a[2:3] = ins
        b[slice(2,3)] = ins
        c[2:3:] = ins

    def test_iterationcontains(self):
        a = array.array(self.typecode, range(10))
        self.assertEqual(list(a), list(range(10)))
        b = array.array(self.typecode, [20])
        self.assertEqual(a[-1] in a, True)
        self.assertEqual(b[0] not in a, True)

    def check_overflow(self, lower, upper):
        # method to be used by subclasses

        # should not overflow assigning lower limit
        a = array.array(self.typecode, [lower])
        a[0] = lower
        # should overflow assigning less than lower limit
        self.assertRaises(OverflowError, array.array, self.typecode, [lower-1])
        self.assertRaises(OverflowError, a.__setitem__, 0, lower-1)
        # should not overflow assigning upper limit
        a = array.array(self.typecode, [upper])
        a[0] = upper
        # should overflow assigning more than upper limit
        self.assertRaises(OverflowError, array.array, self.typecode, [upper+1])
        self.assertRaises(OverflowError, a.__setitem__, 0, upper+1)

    def test_subclassing(self):
        typecode = self.typecode
        class ExaggeratingArray(array.array):
            __slots__ = ['offset']

            def __new__(cls, typecode, data, offset):
                return array.array.__new__(cls, typecode, data)

            def __init__(self, typecode, data, offset):
                self.offset = offset

            def __getitem__(self, i):
                return array.array.__getitem__(self, i) + self.offset

        a = ExaggeratingArray(self.typecode, [3, 6, 7, 11], 4)
        self.assertEntryEqual(a[0], 7)

        self.assertRaises(AttributeError, setattr, a, "color", "blue")

    def test_frombytearray(self):
        a = array.array('b', range(10))
        b = array.array(self.typecode, a)
        self.assertEqual(a, b)

class IntegerNumberTest(NumberTest):
    def test_type_error(self):
        a = array.array(self.typecode)
        a.append(42)
        with self.assertRaises(TypeError):
            a.append(42.0)
        with self.assertRaises(TypeError):
            a[0] = 42.0

class Intable:
    def __init__(self, num):
        self._num = num
    def __index__(self):
        return self._num
    def __int__(self):
        return self._num
    def __sub__(self, other):
        return Intable(int(self) - int(other))
    def __add__(self, other):
        return Intable(int(self) + int(other))

class SignedNumberTest(IntegerNumberTest):
    example = [-1, 0, 1, 42, 0x7f]
    smallerexample = [-1, 0, 1, 42, 0x7e]
    biggerexample = [-1, 0, 1, 43, 0x7f]
    outside = 23

    def test_overflow(self):
        a = array.array(self.typecode)
        lower = -1 * int(pow(2, a.itemsize * 8 - 1))
        upper = int(pow(2, a.itemsize * 8 - 1)) - 1
        self.check_overflow(lower, upper)
        self.check_overflow(Intable(lower), Intable(upper))

class UnsignedNumberTest(IntegerNumberTest):
    example = [0, 1, 17, 23, 42, 0xff]
    smallerexample = [0, 1, 17, 23, 42, 0xfe]
    biggerexample = [0, 1, 17, 23, 43, 0xff]
    outside = 0xaa

    def test_overflow(self):
        a = array.array(self.typecode)
        lower = 0
        upper = int(pow(2, a.itemsize * 8)) - 1
        self.check_overflow(lower, upper)
        self.check_overflow(Intable(lower), Intable(upper))

    def test_bytes_extend(self):
        s = bytes(self.example)

        a = array.array(self.typecode, self.example)
        a.extend(s)
        self.assertEqual(
            a,
            array.array(self.typecode, self.example+self.example)
        )

        a = array.array(self.typecode, self.example)
        a.extend(bytearray(reversed(s)))
        self.assertEqual(
            a,
            array.array(self.typecode, self.example+self.example[::-1])
        )


class ByteTest(SignedNumberTest, unittest.TestCase):
    typecode = 'b'
    minitemsize = 1

class UnsignedByteTest(UnsignedNumberTest, unittest.TestCase):
    typecode = 'B'
    minitemsize = 1

class ShortTest(SignedNumberTest, unittest.TestCase):
    typecode = 'h'
    minitemsize = 2

class UnsignedShortTest(UnsignedNumberTest, unittest.TestCase):
    typecode = 'H'
    minitemsize = 2

class IntTest(SignedNumberTest, unittest.TestCase):
    typecode = 'i'
    minitemsize = 2

class UnsignedIntTest(UnsignedNumberTest, unittest.TestCase):
    typecode = 'I'
    minitemsize = 2

class LongTest(SignedNumberTest, unittest.TestCase):
    typecode = 'l'
    minitemsize = 4

class UnsignedLongTest(UnsignedNumberTest, unittest.TestCase):
    typecode = 'L'
    minitemsize = 4

class LongLongTest(SignedNumberTest, unittest.TestCase):
    typecode = 'q'
    minitemsize = 8

class UnsignedLongLongTest(UnsignedNumberTest, unittest.TestCase):
    typecode = 'Q'
    minitemsize = 8

class FPTest(NumberTest):
    example = [-42.0, 0, 42, 1e5, -1e10]
    smallerexample = [-42.0, 0, 42, 1e5, -2e10]
    biggerexample = [-42.0, 0, 42, 1e5, 1e10]
    outside = 23

    def assertEntryEqual(self, entry1, entry2):
        self.assertAlmostEqual(entry1, entry2)

    def test_nan(self):
        a = array.array(self.typecode, [float('nan')])
        b = array.array(self.typecode, [float('nan')])
        self.assertIs(a != b, True)
        self.assertIs(a == b, False)
        self.assertIs(a > b, False)
        self.assertIs(a >= b, False)
        self.assertIs(a < b, False)
        self.assertIs(a <= b, False)

    def test_byteswap(self):
        a = array.array(self.typecode, self.example)
        self.assertRaises(TypeError, a.byteswap, 42)
        if a.itemsize in (1, 2, 4, 8):
            b = array.array(self.typecode, self.example)
            b.byteswap()
            if a.itemsize==1:
                self.assertEqual(a, b)
            else:
                # On alphas treating the byte swapped bit patters as
                # floats/doubles results in floating point exceptions
                # => compare the 8bit string values instead
                self.assertNotEqual(a.tobytes(), b.tobytes())
            b.byteswap()
            self.assertEqual(a, b)

class FloatTest(FPTest, unittest.TestCase):
    typecode = 'f'
    minitemsize = 4

class DoubleTest(FPTest, unittest.TestCase):
    typecode = 'd'
    minitemsize = 8

    def test_alloc_overflow(self):
        from sys import maxsize
        a = array.array('d', [-1]*65536)
        try:
            a *= maxsize//65536 + 1
        except MemoryError:
            pass
        else:
            self.fail("Array of size > maxsize created - MemoryError expected")
        b = array.array('d', [ 2.71828183, 3.14159265, -1])
        try:
            b * (maxsize//3 + 1)
        except MemoryError:
            pass
        else:
            self.fail("Array of size > maxsize created - MemoryError expected")


class LargeArrayTest(unittest.TestCase):
    typecode = 'b'

    def example(self, size):
        # We assess a base memuse of <=2.125 for constructing this array
        base = array.array(self.typecode, [0, 1, 2, 3, 4, 5, 6, 7]) * (size // 8)
        base += array.array(self.typecode, [99]*(size % 8) + [8, 9, 10, 11])
        return base

    @support.bigmemtest(_2G, memuse=2.125)
    def test_example_data(self, size):
        example = self.example(size)
        self.assertEqual(len(example), size+4)

    @support.bigmemtest(_2G, memuse=2.125)
    def test_access(self, size):
        example = self.example(size)
        self.assertEqual(example[0], 0)
        self.assertEqual(example[-(size+4)], 0)
        self.assertEqual(example[size], 8)
        self.assertEqual(example[-4], 8)
        self.assertEqual(example[size+3], 11)
        self.assertEqual(example[-1], 11)

    @support.bigmemtest(_2G, memuse=2.125+1)
    def test_slice(self, size):
        example = self.example(size)
        self.assertEqual(list(example[:4]), [0, 1, 2, 3])
        self.assertEqual(list(example[-4:]), [8, 9, 10, 11])
        part = example[1:-1]
        self.assertEqual(len(part), size+2)
        self.assertEqual(part[0], 1)
        self.assertEqual(part[-1], 10)
        del part
        part = example[::2]
        self.assertEqual(len(part), (size+5)//2)
        self.assertEqual(list(part[:4]), [0, 2, 4, 6])
        if size % 2:
            self.assertEqual(list(part[-2:]), [9, 11])
        else:
            self.assertEqual(list(part[-2:]), [8, 10])

    @support.bigmemtest(_2G, memuse=2.125)
    def test_count(self, size):
        example = self.example(size)
        self.assertEqual(example.count(0), size//8)
        self.assertEqual(example.count(11), 1)

    @support.bigmemtest(_2G, memuse=2.125)
    def test_append(self, size):
        example = self.example(size)
        example.append(12)
        self.assertEqual(example[-1], 12)

    @support.bigmemtest(_2G, memuse=2.125)
    def test_extend(self, size):
        example = self.example(size)
        example.extend(iter([12, 13, 14, 15]))
        self.assertEqual(len(example), size+8)
        self.assertEqual(list(example[-8:]), [8, 9, 10, 11, 12, 13, 14, 15])

    @support.bigmemtest(_2G, memuse=2.125)
    def test_frombytes(self, size):
        example = self.example(size)
        example.frombytes(b'abcd')
        self.assertEqual(len(example), size+8)
        self.assertEqual(list(example[-8:]), [8, 9, 10, 11] + list(b'abcd'))

    @support.bigmemtest(_2G, memuse=2.125)
    def test_fromlist(self, size):
        example = self.example(size)
        example.fromlist([12, 13, 14, 15])
        self.assertEqual(len(example), size+8)
        self.assertEqual(list(example[-8:]), [8, 9, 10, 11, 12, 13, 14, 15])

    @support.bigmemtest(_2G, memuse=2.125)
    def test_index(self, size):
        example = self.example(size)
        self.assertEqual(example.index(0), 0)
        self.assertEqual(example.index(1), 1)
        self.assertEqual(example.index(7), 7)
        self.assertEqual(example.index(11), size+3)

    @support.bigmemtest(_2G, memuse=2.125)
    def test_insert(self, size):
        example = self.example(size)
        example.insert(0, 12)
        example.insert(10, 13)
        example.insert(size+1, 14)
        self.assertEqual(len(example), size+7)
        self.assertEqual(example[0], 12)
        self.assertEqual(example[10], 13)
        self.assertEqual(example[size+1], 14)

    @support.bigmemtest(_2G, memuse=2.125)
    def test_pop(self, size):
        example = self.example(size)
        self.assertEqual(example.pop(0), 0)
        self.assertEqual(example[0], 1)
        self.assertEqual(example.pop(size+1), 10)
        self.assertEqual(example[size+1], 11)
        self.assertEqual(example.pop(1), 2)
        self.assertEqual(example[1], 3)
        self.assertEqual(len(example), size+1)
        self.assertEqual(example.pop(), 11)
        self.assertEqual(len(example), size)

    @support.bigmemtest(_2G, memuse=2.125)
    def test_remove(self, size):
        example = self.example(size)
        example.remove(0)
        self.assertEqual(len(example), size+3)
        self.assertEqual(example[0], 1)
        example.remove(10)
        self.assertEqual(len(example), size+2)
        self.assertEqual(example[size], 9)
        self.assertEqual(example[size+1], 11)

    @support.bigmemtest(_2G, memuse=2.125)
    def test_reverse(self, size):
        example = self.example(size)
        example.reverse()
        self.assertEqual(len(example), size+4)
        self.assertEqual(example[0], 11)
        self.assertEqual(example[3], 8)
        self.assertEqual(example[-1], 0)
        example.reverse()
        self.assertEqual(len(example), size+4)
        self.assertEqual(list(example[:4]), [0, 1, 2, 3])
        self.assertEqual(list(example[-4:]), [8, 9, 10, 11])

    # list takes about 9 bytes per element
    @support.bigmemtest(_2G, memuse=2.125+9)
    def test_tolist(self, size):
        example = self.example(size)
        ls = example.tolist()
        self.assertEqual(len(ls), len(example))
        self.assertEqual(ls[:8], list(example[:8]))
        self.assertEqual(ls[-8:], list(example[-8:]))

if __name__ == "__main__":
    unittest.main()