codon/test/core/containers.codon

from copy import copy, deepcopy

@tuple
class A:
    a: int
    b: float

    def __getitem__(self: A, n: int):
        return 1

    def __getitem__(self: A, x: Slice):
        if x.start is None and x.stop is None:
            return -1
        if x.start is None:
            return 2
        elif x.stop is None:
            return 3
        else:
            return self.a

@test
def test_tuple():
    def test_in():
        for i in range(10):
            yield i, i in (4, 9, 10, -1, 3, 1), i in (7,)
    assert list(test_in()) == [(0, False, False), (1, True, False), (2, False, False), (3, True, False), (4, True, False), (5, False, False), (6, False, False), (7, False, True), (8, False, False), (9, True, False)]

    def test_cmp[T](a: T, b: T):
        yield 'EQ', a == b
        yield 'NE', a != b
        yield 'LT', a < b
        yield 'GT', a > b
        yield 'LE', a <= b
        yield 'GE', a >= b

    assert list(test_cmp((1,2), (1,2))) == [('EQ', True), ('NE', False), ('LT', False), ('GT', False), ('LE', True), ('GE', True)]
    assert list(test_cmp((1,2,2), (1,2,3))) == [('EQ', False), ('NE', True), ('LT', True), ('GT', False), ('LE', True), ('GE', False)]
    assert list(test_cmp((1,2,-1), (1,0,1))) == [('EQ', False), ('NE', True), ('LT', False), ('GT', True), ('LE', False), ('GE', True)]
    assert list(test_cmp((), ())) == [('EQ', True), ('NE', False), ('LT', False), ('GT', False), ('LE', True), ('GE', True)]

    t = (1,2,3)
    assert (t[0], t[1], t[2]) == (1, 2, 3)
    assert (t[-1], t[-2], t[-3]) == (3, 2, 1)
    assert t[1:3] == (2, 3)
    assert t[-3:1] == (1,)
    assert t[-10:2] == (1, 2)
    assert t[0:] == (1, 2, 3)
    assert t[-2:] == (2, 3)
    assert t[3:] == ()
    assert t[:-1] == (1, 2)
    assert t[:1] == (1,)
    assert t[:] == (1, 2, 3)
    assert t[1::1] == (2, 3)
    assert t[:2:1] == (1, 2)
    assert t[::2] == (1, 3)
    assert t[::-1] == (3, 2, 1)
    assert t[0:3:-1] == ()
    assert t[3:0:-1] == (3, 2, 1)

    a = A(42, 3.14)
    assert a[0] == 1
    assert a[:1] == 2
    assert a[0:] == 3
    assert a[0:1] == 42
    assert a[:] == -1
test_tuple()

@test
def test_list():
    l1 = [i+1 for i in range(100)]
    assert len(l1) == 100
    l1 = l1[98:]
    l2 = [1, 2] * 2

    assert [a for a in l1] == [99, 100]
    assert [a for a in l2] == [1, 2, 1, 2]

    l1 = [i*2 for i in range(3)]
    l1.insert(0, 99)
    l1[0] += 1
    del l1[1]
    assert [a for a in l1[0:3]] == [100, 2, 4]

    l3 = [1, 2, 3]
    assert l3.remove(2) == True
    assert l3.remove(2) == False
    assert l3 == [1, 3]
    assert list[int]().remove(0) == False

    # l4 = [5, 1, 4, 2, 1, -10, 10, 100, -100]
    # assert sorted(l4) == [-100, -10, 1, 1, 2, 4, 5, 10, 100]
    #l4.sort()
    #assert l4 == [-100, -10, 1, 1, 2, 4, 5, 10, 100]
    #assert str(sorted(list[int]())) == "[]"

    l5 = [11, 22, 33, 44]
    del l5[-1]
    assert l5 == [11, 22, 33]
    l5.insert(-1, 55)
    l5.insert(1000, 66)
    l5.insert(-100, 77)
    assert l5 == [77, 11, 22, 55, 33, 66]
    l5 = [11, 22, 55, 33]
    assert l5 + [1,2,3] == [11, 22, 55, 33, 1, 2, 3]
    l5 += [1,2,3]
    assert l5 == [11, 22, 55, 33, 1, 2, 3]
    assert l5.pop() == 3
    assert l5 * 2 == [11, 22, 55, 33, 1, 2, 11, 22, 55, 33, 1, 2]
    l5 *= 2
    assert l5 == [11, 22, 55, 33, 1, 2, 11, 22, 55, 33, 1, 2]
    assert l5.index(33) == 3
    l5 *= 0
    assert len(l5) == 0

    l6 = []
    l6.extend('abc')
    l6.extend(['xyz'])
    l6.extend('')
    assert l6 == ['a', 'b', 'c', 'xyz']

    assert List[int]().copy() == List[int]()
    assert [1,2,3].copy() == [1,2,3]

    def test_cmp[T](a: T, b: T):
        yield 'EQ', a == b
        yield 'NE', a != b
        yield 'LT', a < b
        yield 'GT', a > b
        yield 'LE', a <= b
        yield 'GE', a >= b

    assert list(test_cmp([1,2], [1,2])) == [('EQ', True), ('NE', False), ('LT', False), ('GT', False), ('LE', True), ('GE', True)]
    assert list(test_cmp([1,2,2], [1,2,3])) == [('EQ', False), ('NE', True), ('LT', True), ('GT', False), ('LE', True), ('GE', False)]
    assert list(test_cmp([1,2,-1], [1,0,1])) == [('EQ', False), ('NE', True), ('LT', False), ('GT', True), ('LE', False), ('GE', True)]
    assert list(test_cmp(List[int](), List[int]())) == [('EQ', True), ('NE', False), ('LT', False), ('GT', False), ('LE', True), ('GE', True)]
    assert list(test_cmp([1], List[int]())) == [('EQ', False), ('NE', True), ('LT', False), ('GT', True), ('LE', False), ('GE', True)]
    assert list(test_cmp(List[int](), [1])) == [('EQ', False), ('NE', True), ('LT', True), ('GT', False), ('LE', True), ('GE', False)]
    assert list(test_cmp([1,2,-1], [2])) == [('EQ', False), ('NE', True), ('LT', True), ('GT', False), ('LE', True), ('GE', False)]
    assert list(test_cmp([1,2,-1], [1,2,-1,3])) == [('EQ', False), ('NE', True), ('LT', True), ('GT', False), ('LE', True), ('GE', False)]
    assert list(test_cmp([1,2,-1,3], [1,2,-1])) == [('EQ', False), ('NE', True), ('LT', False), ('GT', True), ('LE', False), ('GE', True)]

    assert str([1] + [2] + [] + [3]) == '[1, 2, 3]'
    assert ['a', 'b'] + ['x', 'y', 'z'] == ['a', 'b'] + ['x', 'y', 'z']
    assert [(1,1), (2,2)] + [] == [(1,1), (2,2)]
    assert [] + [(1,1), (2,2)] == [(1,1), (2,2)]
    assert List[int]() + List[int]() == List[int]()
    l7 = [3.14, 2.5]
    l7 += [9.99, -1.0]
    assert l7 == [3.14, 2.5, 9.99, -1.0]
    l8 = []
    l8 += [11, 22, 33]
    assert l8 == [11, 22, 33]
    l8 = [11, 22, 33]
    l8 += []
    assert l8 == [11, 22, 33]
    l8 = List[int]()
    l8 += List[int]()
    assert l8 == List[int]()
test_list()

@test
def test_setslice():
    l = [0, 1]
    a = l

    for i in range(-3, 4):
        a[:i] = l[:i]
        assert a == l
        a2 = a[:]
        a2[:i] = a[:i]
        assert a2 == a
        a[i:] = l[i:]
        assert a == l
        a2 = a[:]
        a2[i:] = a[i:]
        assert a2 == a
        for j in range(-3, 4):
            a[i:j] = l[i:j]
            assert a == l
            a2 = a[:]
            a2[i:j] = a[i:j]
            assert a2 == a

    a2 = a[:]
    aa2 = a2[:]
    aa2[:0] = [-2, -1]
    assert aa2 == [-2, -1, 0, 1]
    aa2[0:] = list[int]()
    assert aa2 == list[int]()

    a = [1, 2, 3, 4, 5]
    a[:-1] = a
    assert a == [1, 2, 3, 4, 5, 5]
    a = [1, 2, 3, 4, 5]
    a[1:] = a
    assert a == [1, 1, 2, 3, 4, 5]
    a = [1, 2, 3, 4, 5]
    a[1:-1] = a
    assert a == [1, 1, 2, 3, 4, 5, 5]

    a = list[int]()
    a[:] = list(range(10))
    assert a == list(range(10))

    a = list(range(20))
    try:
        a[0:10:0] = [1,2,3]
        assert False
    except ValueError:
        pass

    try:
        a[0:10:2] = [1,2]
        assert False
    except ValueError:
        pass

    a[2:10:3] = [1,2,3]
    assert a == [0, 1, 1, 3, 4, 2, 6, 7, 3, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
test_setslice()

@test
def test_delslice():
    a = [0, 1]
    del a[1:2]
    del a[0:1]
    assert a == list[int]()

    a = [0, 1]
    del a[1:2]
    del a[0:1]
    assert a == list[int]()

    a = [0, 1]
    del a[-2:-1]
    assert a == [1]

    a = [0, 1]
    del a[-2:-1]
    assert a == [1]

    a = [0, 1]
    del a[1:]
    del a[:1]
    assert a == list[int]()

    a = [0, 1]
    del a[1:]
    del a[:1]
    assert a == list[int]()

    a = [0, 1]
    del a[-1:]
    assert a == [0]

    a = [0, 1]
    del a[-1:]
    assert a == [0]

    a = [0,1]
    del a[:]
    assert a == list[int]()
test_delslice()

@test
def test_extendedslicing():
    a = [0,1,2,3,4]
    del a[::2]
    assert a == [1,3]

    a = list(range(5))
    del a[1::2]
    assert a == [0,2,4]

    a = list(range(5))
    del a[1::-2]
    assert a == [0,2,3,4]

    a = list(range(10))
    del a[::1000]
    assert a == [1, 2, 3, 4, 5, 6, 7, 8, 9]

    a = list(range(10))
    a[::2] = [-1]*5
    assert a == [-1, 1, -1, 3, -1, 5, -1, 7, -1, 9]

    a = list(range(10))
    a[::-4] = [10]*3
    assert a == [0, 10, 2, 3, 4, 10, 6, 7, 8 ,10]

    a = list(range(4))
    a[::-1] = a
    assert a == [3, 2, 1, 0]

    a = list(range(10))
    b = a[:]
    c = a[:]
    a[2:3] = [222, 333]
    b[2:3] = [222, 333]
    c[2:3:] = [222, 333]
    assert a == b
    assert a == c

    a = list(range(10))
    a[::2] = (0, 1, 2, 3, 4)
    assert a == [0, 1, 1, 3, 2, 5, 3, 7, 4, 9]
test_extendedslicing()

@test
def test_set():
    s1 = {a for a in range(100)}
    assert len(s1) == 100
    s1 = {a%8 for a in range(100)}
    for a in range(8):
        assert a in s1
    for a in range(8,100):
        assert a not in s1

    assert 5 in s1
    s1.remove(5)
    assert 5 not in s1
    assert len(s1) == 7

    s1 = {1,2,3,4}
    s2 = {2,3,4,5}
    s3 = set[int]()

    assert (s1 | s2) == {1, 2, 3, 4, 5}
    assert (s1 & s2) == {4, 2, 3}
    assert (s1 ^ s2) == {1, 5}
    assert (s1 | s3) == {1, 2, 3, 4}
    assert (s1 & s3) == set[int]()
    assert (s1 ^ s3) == {1, 2, 3, 4}
    assert (s1 - s2) == {1}
    assert (s2 - s1) == {5}
    assert (s3 - s1 - s2) == set[int]()
    assert (s1 > s2) == False
    assert (s1 < s2) == False
    assert (s3 <= s1) == True
    assert (s2 >= s1) == False
    assert ((s1 | s2) > s1) == True

    s1c = copy(s1)
    s2c = copy(s2)
    s3c = copy(s3)

    assert s1c == {1, 2, 3, 4}
    s1c &= s2c
    assert s1c == {2, 3, 4}
    s1c -= s3c
    assert s1c == {2, 3, 4}
    s1c ^= s1c
    assert s1c == set[int]()
    s1c |= s2c
    assert s1c == {2, 3, 4, 5}
    assert s1 == {1, 2, 3, 4}

    s1 = {1, 2, 3, 999999}
    s2 = {1, 2, 3, 999999}
    v = s1.pop()
    assert v in s2
    s2.remove(v)

    v = s1.pop()
    assert v in s2
    s2.remove(v)

    v = s1.pop()
    assert v in s2
    s2.remove(v)

    v = s1.pop()
    assert v in s2
    s2.remove(v)

    try:
        s1.pop()
        assert False
    except ValueError:
        pass
test_set()

@test
def test_dict():
    d1 = copy({a: a*a for a in range(100)})
    assert len(d1) == 100
    d1 = {a: a*a for a in range(5)}
    assert len(copy(dict[int,int]())) == 0

    assert [d1.get(a, -1) for a in range(6)] == [0, 1, 4, 9, 16, -1]

    assert 2 in d1
    del d1[2]
    assert 2 not in d1
    d1[2] = 44
    assert 2 in d1
    assert d1.get(2, -1) == 44
    assert d1[3] == 9

    del d1[3]
    del d1[4]

    assert [k for k in d1] == [0, 1, 2]
    assert [t for t in d1.items()] == [(0, 0), (1, 1), (2, 44)]

    d2 = {'x': 10, 'y': 0}
    d2.increment('x')
    d2.increment('y', by=-1)
    d2.increment('z', by=2)
    assert d2['x'] == 11
    assert d2['y'] == -1
    assert d2['z'] == 2
    assert d2 == {'x': 11, 'y': -1, 'z': 2}

    d3 = {1: 2, 42: 42}
    d4 = {1: 5, 2: 9}
    assert d3 | d4 == {1: 5, 42: 42, 2: 9}
    d3 |= d4
    assert d3 == {1: 5, 42: 42, 2: 9}
test_dict()

@test
def test_deque():
    from collections import deque

    dq = deque[int]()
    dq.append(1)
    dq.append(2)
    dq.append(3)
    dq.appendleft(11)
    dq.appendleft(22)
    assert str(dq) == 'deque([22, 11, 1, 2, 3])'
    assert bool(dq) == True

    # test cap increase:
    dq.clear()
    assert bool(dq) == False
    for i in range(20):
        dq.append(i)
        dq.appendleft(i)
    assert str(dq) == 'deque([19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19])'
    assert len(dq) == 40

    for i in range(19):
        dq.pop()
        dq.popleft()
    assert str(dq) == 'deque([0, 0])'
    for a in dq:
        assert a == 0

    assert (0 in dq) == True
    assert (1 in dq) == False
    assert str(copy(dq)) == 'deque([0, 0])'

    # test maxlen:
    dq = deque[int](5)
    for i in range(100):
        dq.append(i)
    assert str(dq) == 'deque([95, 96, 97, 98, 99])'

    for i in range(5):
        dq.append(i)
    assert str(dq) == 'deque([0, 1, 2, 3, 4])'
test_deque()

@test
def test_counter():
    from collections import Counter

    # main
    c = Counter('abcaba')
    assert c == Counter({'a':3 , 'b': 2, 'c': 1})
    assert len(c) == 3
    assert sum(c.values()) == 6
    assert set(c.values()) == {1, 2, 3}
    assert set(c.keys()) == {'a','b','c'}
    assert set(c.items()) == {('a',3), ('b',2), ('c',1)}
    assert c['b'] == 2
    assert c['z'] == 0
    assert c.__contains__('b')
    assert not c.__contains__('z')
    assert c.get('b', 10) == 2
    assert c.get('z', 10) == 10
    assert c == {'a':3 , 'b': 2, 'c': 1}
    assert c.most_common() == [('a', 3), ('b', 2), ('c', 1)]
    for i in range(5):
        assert c.most_common(i) == [('a', 3), ('b', 2), ('c', 1)][:i]

    c['a'] += 1         # increment an existing value
    c['b'] -= 2         # sub existing value to zero
    del c['c']          # remove an entry
    del c['c']          # make sure that del doesn't raise KeyError
    c['d'] -= 2         # sub from a missing value
    c['e'] = -5         # directly assign a missing value
    c['f'] += 4         # add to a missing value

    assert dict(c) == {'a':4, 'b':0, 'd':-2, 'e':-5, 'f':4}
    assert c.pop('f') == 4
    assert 'f' not in c
    for i in range(3):
        elem, cnt = c.popitem()
        assert elem not in c
    c.clear()
    assert c == {}
    c.update({'a':5, 'b':3})
    c.update({'c': 1})
    c.update(Counter('a' * 50 + 'b' * 30))
    c.update()
    c.update('a' * 500 + 'b' * 300)
    c.update('cdc')
    assert c == {'a':555, 'b':333, 'c':3, 'd':1}

    assert c.setdefault('d',5) == 1
    assert c['d'] == 1
    assert c.setdefault('e', 5) == 5
    assert c['e'] == 5


    # total
    c = Counter({'a':10, 'b':5, 'c':0})
    assert c.total() == 15


    # conversions
    s = 'she sells sea shells by the sea shore'
    assert sorted(Counter(s).elements()) == sorted(s)
    assert sorted(Counter(s)) == sorted(set(s))
    assert dict(Counter(s)) == dict(Counter(s).items())
    assert set(Counter(s)) == set(s)


    # in invariant
    c = Counter({'a':10, 'b':-2, 'c':0})
    for elem in c:
        assert elem in c


    # multiset
    c = Counter({'a':10, 'b':-2, 'c':0}) + Counter()
    assert dict(c) == {'a':10}

    from random import randrange, randint
    elements = 'abcd'
    for i in range(1000):
        # test random pairs of multisets
        p = Counter(dict((elem, randrange(-2,4)) for elem in elements))
        p.update({'e':1, 'f':-1, 'g':0})
        q = Counter(dict((elem, randrange(-2,4)) for elem in elements))
        q.update({'h':1, 'i':-1, 'j':0})

        result = p + q
        for x in elements:
            assert max(0, p[x] + q[x]) == result[x]
        assert all(x>0 for x in result.values())

        result = p - q
        for x in elements:
            assert max(0, p[x] - q[x]) == result[x]
        assert all(x>0 for x in result.values())

        result = p | q
        for x in elements:
            assert max(0, p[x], q[x]) == result[x]
        assert all(x>0 for x in result.values())

        result = p & q
        for x in elements:
            assert max(0, min(p[x], q[x])) == result[x]
        assert all(x>0 for x in result.values())

    elements = 'abcdef'
    for i in range(100):
        # verify that random multisets with no repeats are exactly like sets
        p = Counter(dict((elem, randrange(0, 2)) for elem in elements))
        q = Counter(dict((elem, randrange(0, 2)) for elem in elements))

        counter_result = p - q
        set_result = set(p.elements()) - set(q.elements())
        assert counter_result == dict.fromkeys(set_result, 1)

        counter_result = p | q
        set_result = set(p.elements()) | set(q.elements())
        assert counter_result == dict.fromkeys(set_result, 1)

        counter_result = p & q
        set_result = set(p.elements()) & set(q.elements())
        assert counter_result == dict.fromkeys(set_result, 1)


    # in-place
    elements = 'abcd'
    for i in range(1000):
        # test random pairs of multisets
        p = Counter(dict((elem, randrange(-2,4)) for elem in elements))
        p.update({'e':1, 'f':-1, 'g':0})
        q = Counter(dict((elem, randrange(-2,4)) for elem in elements))
        q.update({'h':1, 'i':-1, 'j':0})

        c = p.copy()
        c_id = id(c)
        regular_result = c + q
        inplace_result = c.__iadd__(q)
        assert inplace_result == regular_result
        assert id(inplace_result) == c_id

        c = p.copy()
        c_id = id(c)
        regular_result = c - q
        inplace_result = c.__isub__(q)
        assert inplace_result == regular_result
        assert id(inplace_result) == c_id

        c = p.copy()
        c_id = id(c)
        regular_result = c | q
        inplace_result = c.__ior__(q)
        assert inplace_result == regular_result
        assert id(inplace_result) == c_id

        c = p.copy()
        c_id = id(c)
        regular_result = c & q
        inplace_result = c.__iand__(q)
        assert inplace_result == regular_result
        assert id(inplace_result) == c_id


    # subtract
    c = Counter({'a':-5, 'b':0, 'c':5, 'd':10, 'e':15,'g':40})
    c.subtract({'a':1, 'b':2, 'c':-3, 'd':10, 'e':20, 'f':30, 'h':-50})
    assert c == Counter({'a':-6, 'b':-2, 'c':8, 'd':0, 'e':-5, 'f':-30, 'g':40, 'h':50})
    c = Counter({'a':-5, 'b':0, 'c':5, 'd':10, 'e':15,'g':40})
    c.subtract(Counter({'a':1, 'b':2, 'c':-3, 'd':10, 'e':20, 'f':30, 'h':-50}))
    assert c == Counter({'a':-6, 'b':-2, 'c':8, 'd':0, 'e':-5, 'f':-30, 'g':40, 'h':50})

    c = Counter('aaabbcd')
    c.subtract('aaaabbcce')
    assert c == Counter({'a':-1, 'b':0, 'c':-1, 'd':1, 'e':-1})

    c = Counter()
    c.subtract({'self':42})
    assert list(c.items()) == [('self', -42)]
    c = Counter()
    c.subtract({'iterable':42})
    assert list(c.items()) == [('iterable', -42)]


    # unary
    c = Counter({'a':-5, 'b':0, 'c':5, 'd':10, 'e':15, 'g':40})
    assert dict(+c) == {'c':5, 'd':10, 'e':15, 'g':40}
    assert dict(-c) == {'a':5}


    # equality
    assert Counter({'a':3, 'b':2}) == Counter('ababa')
    assert Counter({'a':3, 'b':2}) != Counter('babab')


    # most common
    c = Counter({v:k for k,v in enumerate('hgfedcba')})
    q = [(v,k) for k,v in enumerate('hgfedcba')][::-1]
    assert c.most_common() == q
    for i in range(10):
        assert c.most_common(i) == q[:i]

    for limit in range(100):
        for samples in range(100):
            for most_common in range(100):
                data = [randint(0, limit) for _ in range(samples)]
                d = Counter(data)
                exp = sorted(d.values(), reverse=True)[:most_common]
                got = [v for k,v in d.most_common(most_common)]
                assert exp == got

    for limit in range(100):
        for samples in range(100):
            data = [randint(0, limit) for _ in range(samples)]
            d = Counter(data)
            exp = sorted(d.values(), reverse=True)
            got = [v for k,v in d.most_common()]
            assert exp == got

    assert repr(Counter('abcabc')) == "Counter({'a': 2, 'b': 2, 'c': 2})"
test_counter()

@test
def test_defaultdict():
    from collections import defaultdict

    # basic
    #d1 = defaultdict()
    #self.assertEqual(d1.default_factory, None)
    #d1.default_factory = list
    d1 = defaultdict(list)
    d1[12].append(42)
    assert d1 == {12: [42]}
    d1[12].append(24)
    assert d1 == {12: [42, 24]}
    d1[13]
    d1[14]
    assert d1 == {12: [42, 24], 13: [], 14: []}
    assert d1[12] is not d1[13] is not d1[14]
    #d2 = defaultdict(list, foo=1, bar=2)
    #self.assertEqual(d2.default_factory, list)
    #self.assertEqual(d2, {"foo": 1, "bar": 2})
    #self.assertEqual(d2["foo"], 1)
    #self.assertEqual(d2["bar"], 2)
    #self.assertEqual(d2[42], [])
    #self.assertIn("foo", d2)
    #self.assertIn("foo", d2.keys())
    #self.assertIn("bar", d2)
    #self.assertIn("bar", d2.keys())
    #self.assertIn(42, d2)
    #self.assertIn(42, d2.keys())
    #self.assertNotIn(12, d2)
    #self.assertNotIn(12, d2.keys())
    #d2.default_factory = None
    #self.assertEqual(d2.default_factory, None)
    #try:
    #    d2[15]
    #except KeyError as err:
    #    self.assertEqual(err.args, (15,))
    #else:
    #    self.fail("d2[15] didn't raise KeyError")
    #self.assertRaises(TypeError, defaultdict, 1)

    # missing
    #d1 = defaultdict()
    #self.assertRaises(KeyError, d1.__missing__, 42)
    #d1.default_factory = list
    #d1 = defaultdict(list)
    assert d1.__missing__(42) == []

    # repr
    d1 = defaultdict(lambda: 0)
    #self.assertEqual(d1.default_factory, None)
    #self.assertEqual(repr(d1), "defaultdict(None, {})")
    #self.assertEqual(eval(repr(d1)), d1)
    d1[11] = 41
    assert repr(d1) == "defaultdict(<default factory of 'int'>, {11: 41})"
    d2 = defaultdict(lambda: 0)  # TODO: use 'int' when it's fixed...
    #self.assertEqual(d2.default_factory, int)
    d2[12] = 42
    assert repr(d2) == "defaultdict(<default factory of 'int'>, {12: 42})"
    def foo(): return 43
    d3 = defaultdict(foo)
    #self.assertTrue(d3.default_factory is foo)
    d3[13]
    assert repr(d3) == "defaultdict(<default factory of 'int'>, {13: 43})"


    # copy
    d1 = defaultdict(list)
    d2 = d1.copy()
    #self.assertEqual(type(d2), defaultdict)
    #self.assertEqual(d2.default_factory, None)
    assert d2 == {}
    #d1.default_factory = list
    #d3 = d1.copy()
    #self.assertEqual(type(d3), defaultdict)
    #self.assertEqual(d3.default_factory, list)
    #self.assertEqual(d3, {})
    d1[42].append(0)
    #d4 = d1.copy()
    #assert d4 == {42: [0]}
    #d4[12]
    #assert d4 == {42: [], 12: []}

    # Issue 6637: Copy fails for empty default dict
    #d = defaultdict()
    #d['a'] = 42
    #e = d.copy()
    #assert e['a'] == 42


    # shallow copy
    foobar = list
    d1 = defaultdict(foobar)
    d1[1] += [1]
    d2 = copy(d1)
    #self.assertEqual(d2.default_factory, foobar)
    assert d2 == d1
    #d1.default_factory = list
    d2 = copy(d1)
    #self.assertEqual(d2.default_factory, list)
    assert d2 == d1

    # deep copy
    d1 = defaultdict(foobar)
    d1[1].append(1)
    d2 = deepcopy(d1)
    #self.assertEqual(d2.default_factory, foobar)
    assert d2 == d1
    assert d1[1] is not d2[1]
    #d1.default_factory = list
    d2 = deepcopy(d1)
    #self.assertEqual(d2.default_factory, list)
    assert d2 == d1

    # KeyError without factory
    #d1 = defaultdict()
    #try:
    #    d1[(1,)]
    #except KeyError as err:
    #    self.assertEqual(err.args[0], (1,))
    #else:
    #    self.fail("expected KeyError")

    # pickling
    #d = defaultdict(int)
    #d[1]
    #for proto in range(pickle.HIGHEST_PROTOCOL + 1):
    #    s = pickle.dumps(d, proto)
    #    o = pickle.loads(s)
    #    self.assertEqual(d, o)

    # union
    i = defaultdict(int, {1: 1, 2: 2})
    s = defaultdict(int, {0: 0, 1: 111})

    i_s = i | s
    #self.assertIs(i_s.default_factory, int)
    assert i_s == {1: 111, 2: 2, 0: 0}
    assert sorted(i_s) == [0, 1, 2]

    s_i = s | i
    #self.assertIs(s_i.default_factory, str)
    assert s_i == {0: 0, 1: 1, 2: 2}
    assert sorted(s_i) == [0, 1, 2]

    i_ds = i | dict(s)
    #self.assertIs(i_ds.default_factory, int)
    assert i_ds == {1: 111, 2: 2, 0: 0}
    assert sorted(i_ds) == [0, 1, 2]

    ds_i = dict(s) | i
    #self.assertIs(ds_i.default_factory, int)
    assert ds_i == {0: 0, 1: 1, 2: 2}
    assert sorted(ds_i) == [0, 1, 2]

    # We inherit a fine |= from dict, so just a few sanity checks here:
    i |= list(s.items())
    #self.assertIs(i.default_factory, int)
    assert i == {1: 111, 2: 2, 0: 0}
    assert sorted(i), [1, 2, 0]

    # general
    s = 'mississippi'
    d = defaultdict(int)
    for k in s:
        d[k] += 1
    assert sorted(d.items()) == [('i', 4), ('m', 1), ('p', 2), ('s', 4)]

    s = 'mississippi'
    d = defaultdict(int)
    for k in s:
        d[k] = d.get(k, 0) + 1
    assert sorted(d.items()) == [('i', 4), ('m', 1), ('p', 2), ('s', 4)]

    s = [('yellow', 1), ('blue', 2), ('yellow', 3), ('blue', 4), ('red', 1)]
    d = defaultdict(list)
    for k, v in s:
        d[k].append(v)
    assert sorted(d.items()) == [('blue', [2, 4]), ('red', [1]), ('yellow', [1, 3])]

    def constant_factory(value):
        return lambda: value

    d = defaultdict(constant_factory('<missing>'))
    assert d[10] == '<missing>'
test_defaultdict()