import unittest

import sys

from test import test_support

class G:

    'Sequence using __getitem__'

    def __init__(self, seqn):

        self.seqn = seqn

    def __getitem__(self, i):

        return self.seqn[i]

class I:

    'Sequence using iterator protocol'

    def __init__(self, seqn):

        self.seqn = seqn

        self.i = 0

    def __iter__(self):

        return self

    def next(self):

        if self.i >= len(self.seqn): raise StopIteration

        v = self.seqn[self.i]

        self.i += 1

        return v

class Ig:

    'Sequence using iterator protocol defined with a generator'

    def __init__(self, seqn):

        self.seqn = seqn

        self.i = 0

    def __iter__(self):

        for val in self.seqn:

            yield val

class X:

    'Missing __getitem__ and __iter__'

    def __init__(self, seqn):

        self.seqn = seqn

        self.i = 0

    def next(self):

        if self.i >= len(self.seqn): raise StopIteration

        v = self.seqn[self.i]

        self.i += 1

        return v

class E:

    'Test propagation of exceptions'

    def __init__(self, seqn):

        self.seqn = seqn

        self.i = 0

    def __iter__(self):

        return self

    def next(self):

        3 // 0

class N:

    'Iterator missing next()'

    def __init__(self, seqn):

        self.seqn = seqn

        self.i = 0

    def __iter__(self):

        return self

class EnumerateTestCase(unittest.TestCase):

    enum = enumerate

    seq, res = 'abc', [(0,'a'), (1,'b'), (2,'c')]

    def test_basicfunction(self):

        self.assertEqual(type(self.enum(self.seq)), self.enum)

        e = self.enum(self.seq)

        self.assertEqual(iter(e), e)

        self.assertEqual(list(self.enum(self.seq)), self.res)

        self.enum.__doc__

    def test_getitemseqn(self):

        self.assertEqual(list(self.enum(G(self.seq))), self.res)

        e = self.enum(G(''))

        self.assertRaises(StopIteration, e.next)

    def test_iteratorseqn(self):

        self.assertEqual(list(self.enum(I(self.seq))), self.res)

        e = self.enum(I(''))

        self.assertRaises(StopIteration, e.next)

    def test_iteratorgenerator(self):

        self.assertEqual(list(self.enum(Ig(self.seq))), self.res)

        e = self.enum(Ig(''))

        self.assertRaises(StopIteration, e.next)

    def test_noniterable(self):

        self.assertRaises(TypeError, self.enum, X(self.seq))

    def test_illformediterable(self):

        self.assertRaises(TypeError, list, self.enum(N(self.seq)))

    def test_exception_propagation(self):

        self.assertRaises(ZeroDivisionError, list, self.enum(E(self.seq)))

    def test_argumentcheck(self):

        self.assertRaises(TypeError, self.enum) # no arguments

        self.assertRaises(TypeError, self.enum, 1) # wrong type (not iterable)

        self.assertRaises(TypeError, self.enum, 'abc', 2) # too many arguments

    def test_tuple_reuse(self):

        # Tests an implementation detail where tuple is reused

        # whenever nothing else holds a reference to it

        self.assertEqual(len(set(map(id, list(enumerate(self.seq))))), len(self.seq))

        self.assertEqual(len(set(map(id, enumerate(self.seq)))), min(1,len(self.seq)))

class MyEnum(enumerate):

    pass

class SubclassTestCase(EnumerateTestCase):

    enum = MyEnum

class TestEmpty(EnumerateTestCase):

    seq, res = '', []

class TestBig(EnumerateTestCase):

    seq = range(10,20000,2)

    res = zip(range(20000), seq)

class TestReversed(unittest.TestCase):

    def test_simple(self):

        class A:

            def __getitem__(self, i):

                if i < 5:

                    return str(i)

                raise StopIteration

            def __len__(self):

                return 5

        for data in 'abc', range(5), tuple(enumerate('abc')), A(), xrange(1,17,5):

            self.assertEqual(list(data)[::-1], list(reversed(data)))

        self.assertRaises(TypeError, reversed, {})

    def test_xrange_optimization(self):

        x = xrange(1)

        self.assertEqual(type(reversed(x)), type(iter(x)))

    def test_len(self):

        # This is an implementation detail, not an interface requirement

        from test.test_iterlen import len

        for s in ('hello', tuple('hello'), list('hello'), xrange(5)):

            self.assertEqual(len(reversed(s)), len(s))

            r = reversed(s)

            list(r)

            self.assertEqual(len(r), 0)

        class SeqWithWeirdLen:

            called = False

            def __len__(self):

                if not self.called:

                    self.called = True

                    return 10

                raise ZeroDivisionError

            def __getitem__(self, index):

                return index

        r = reversed(SeqWithWeirdLen())

        self.assertRaises(ZeroDivisionError, len, r)

    def test_gc(self):

        class Seq:

            def __len__(self):

                return 10

            def __getitem__(self, index):

                return index

        s = Seq()

        r = reversed(s)

        s.r = r

    def test_args(self):

        self.assertRaises(TypeError, reversed)

        self.assertRaises(TypeError, reversed, [], 'extra')

    def test_bug1229429(self):

        # this bug was never in reversed, it was in

        # PyObject_CallMethod, and reversed_new calls that sometimes.

        if not hasattr(sys, "getrefcount"):

            return

        def f():

            pass

        r = f.__reversed__ = object()

        rc = sys.getrefcount(r)

        for i in range(10):

            try:

                reversed(f)

            except TypeError:

                pass

            else:

                self.fail("non-callable __reversed__ didn't raise!")

        self.assertEqual(rc, sys.getrefcount(r))

def test_main(verbose=None):

    testclasses = (EnumerateTestCase, SubclassTestCase, TestEmpty, TestBig,

                   TestReversed)

    test_support.run_unittest(*testclasses)

    # verify reference counting

    import sys

    if verbose and hasattr(sys, "gettotalrefcount"):

        counts = [None] * 5

        for i in xrange(len(counts)):

            test_support.run_unittest(*testclasses)

            counts[i] = sys.gettotalrefcount()

        print counts

if __name__ == "__main__":

    test_main(verbose=True)