#!/usr/bin/python
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# Test stream functions

import unittest
from util import *

def testStream():

    s = cons_stream(0, lambda: cons_stream(1, lambda: cons(2, ())))
    assert len(s) == 3
    assert car(s) == 0
    assert cadr(s) == 1
    assert len(cdr(s)) == 2
    assert s[0] == 0
    assert s[1] == 1
    assert s[2] == 2
    assert s[:1] == (0, 1)
    assert s[:5] == (0, 1, 2)
    assert s[2:5] == (2,)
    assert s[4:5] == ()
    assert s[0:] == (0, 1, 2)
    assert (0, 1, 2) == s[0:]

    return True

if __name__ == "__main__":
    print "Testing..."
    testStream()
    print "OK"