from __future__ import generators
from collect import collect
builtin_iter = iter
from iter import iter
import py


def test_simple():
    it1 = iter(xrange(123))
    assert isinstance(it1, collect)  # collect is assumed to be already tested
    assert builtin_iter(it1) is it1
    for x in range(123):
        assert it1.next() == x
    py.test.raises(StopIteration, it1.next)
    py.test.raises(StopIteration, it1.next)

def test_idempotent():
    it1 = iter(xrange(1234))
    it2 = iter(it1)
    it3 = iter(it1)
    assert it1 is it2 is it3

def test_lazy_iter():
    seen = []
    def g():
        for x in range(10):
            seen.append(x)
            yield x
    for y in iter(g()):
        assert seen == [y]
        del seen[:]

def test_two_args():
    buffer = [5,8,2,4]
    it1 = iter(buffer.pop, 8)
    assert it1 == [4,2]

def test_consume():
    expected = [5,8,2,4]
    it1 = iter([5,8,2,4])
    assert it1 == expected
    assert it1[:] == expected
    assert it1 == expected
    assert it1[:] == expected
    for x in it1:
        assert x == expected.pop(0)
        assert it1 == expected
        assert it1[:] == expected
        assert it1 == expected
        assert it1[:] == expected
    assert expected == []

def test_independent():
    it1 = iter([5,8,2,4])
    it2 = iter(it1[:])
    assert zip(it1, it2) == [(5,5), (8,8), (2,2), (4,4)]
    assert not it1
    assert not it2

def test_repr_str():
    it1 = iter(xrange(4))
    assert repr(it1) == 'itercollect([0, 1, 2...)'
    assert str(it1) == 'itercollect([0, 1, 2, 3])'