FCL/sf/adapt/qemu: comparison symbian-qemu-0.9.1-12/python-2.6.1/Lib/test/test

equal deleted inserted replaced

-:ffa851df0825
+:2fb8b9db1c86
+import unittest
+from test import test_support
+from itertools import *
+from weakref import proxy
+import sys
+import operator
+import random
+maxsize = test_support.MAX_Py_ssize_t
+minsize = -maxsize-1
+def onearg(x):
+'Test function of one argument'
+return 2*x
+def errfunc(*args):
+'Test function that raises an error'
+raise ValueError
+def gen3():
+'Non-restartable source sequence'
+for i in (0, 1, 2):
+yield i
+def isEven(x):
+'Test predicate'
+return x%2==0
+def isOdd(x):
+'Test predicate'
+return x%2==1
+class StopNow:
+'Class emulating an empty iterable.'
+def __iter__(self):
+return self
+def next(self):
+raise StopIteration
+def take(n, seq):
+'Convenience function for partially consuming a long of infinite iterable'
+return list(islice(seq, n))
+def prod(iterable):
+return reduce(operator.mul, iterable, 1)
+def fact(n):
+'Factorial'
+return prod(range(1, n+1))
+class TestBasicOps(unittest.TestCase):
+def test_chain(self):
+def chain2(*iterables):
+'Pure python version in the docs'
+for it in iterables:
+for element in it:
+yield element
+for c in (chain, chain2):
+self.assertEqual(list(c('abc', 'def')), list('abcdef'))
+self.assertEqual(list(c('abc')), list('abc'))
+self.assertEqual(list(c('')), [])
+self.assertEqual(take(4, c('abc', 'def')), list('abcd'))
+self.assertRaises(TypeError, list,c(2, 3))
+def test_chain_from_iterable(self):
+self.assertEqual(list(chain.from_iterable(['abc', 'def'])), list('abcdef'))
+self.assertEqual(list(chain.from_iterable(['abc'])), list('abc'))
+self.assertEqual(list(chain.from_iterable([''])), [])
+self.assertEqual(take(4, chain.from_iterable(['abc', 'def'])), list('abcd'))
+self.assertRaises(TypeError, list, chain.from_iterable([2, 3]))
+def test_combinations(self):
+self.assertRaises(TypeError, combinations, 'abc')   # missing r argument
+self.assertRaises(TypeError, combinations, 'abc', 2, 1) # too many arguments
+self.assertRaises(TypeError, combinations, None)        # pool is not iterable
+self.assertRaises(ValueError, combinations, 'abc', -2)  # r is negative
+self.assertRaises(ValueError, combinations, 'abc', 32)  # r is too big
+self.assertEqual(list(combinations(range(4), 3)),
+[(0,1,2), (0,1,3), (0,2,3), (1,2,3)])
+def combinations1(iterable, r):
+'Pure python version shown in the docs'
+pool = tuple(iterable)
+n = len(pool)
+indices = range(r)
+yield tuple(pool[i] for i in indices)
+while 1:
+for i in reversed(range(r)):
+if indices[i] != i + n - r:
+break
+else:
+return
+indices[i] += 1
+for j in range(i+1, r):
+indices[j] = indices[j-1] + 1
+yield tuple(pool[i] for i in indices)
+def combinations2(iterable, r):
+'Pure python version shown in the docs'
+pool = tuple(iterable)
+n = len(pool)
+for indices in permutations(range(n), r):
+if sorted(indices) == list(indices):
+yield tuple(pool[i] for i in indices)
+for n in range(7):
+values = [5*x-12 for x in range(n)]
+for r in range(n+1):
+result = list(combinations(values, r))
+self.assertEqual(len(result), fact(n) / fact(r) / fact(n-r)) # right number of combs
+self.assertEqual(len(result), len(set(result)))         # no repeats
+self.assertEqual(result, sorted(result))                # lexicographic order
+for c in result:
+self.assertEqual(len(c), r)                         # r-length combinations
+self.assertEqual(len(set(c)), r)                    # no duplicate elements
+self.assertEqual(list(c), sorted(c))                # keep original ordering
+self.assert_(all(e in values for e in c))           # elements taken from input iterable
+self.assertEqual(list(c),
+[e for e in values if e in c])      # comb is a subsequence of the input iterable
+self.assertEqual(result, list(combinations1(values, r))) # matches first pure python version
+self.assertEqual(result, list(combinations2(values, r))) # matches first pure python version
+# Test implementation detail:  tuple re-use
+self.assertEqual(len(set(map(id, combinations('abcde', 3)))), 1)
+self.assertNotEqual(len(set(map(id, list(combinations('abcde', 3))))), 1)
+def test_permutations(self):
+self.assertRaises(TypeError, permutations)              # too few arguments
+self.assertRaises(TypeError, permutations, 'abc', 2, 1) # too many arguments
+self.assertRaises(TypeError, permutations, None)        # pool is not iterable
+self.assertRaises(ValueError, permutations, 'abc', -2)  # r is negative
+self.assertRaises(ValueError, permutations, 'abc', 32)  # r is too big
+self.assertRaises(TypeError, permutations, 'abc', 's')  # r is not an int or None
+self.assertEqual(list(permutations(range(3), 2)),
+[(0,1), (0,2), (1,0), (1,2), (2,0), (2,1)])
+def permutations1(iterable, r=None):
+'Pure python version shown in the docs'
+pool = tuple(iterable)
+n = len(pool)
+r = n if r is None else r
+indices = range(n)
+cycles = range(n, n-r, -1)
+yield tuple(pool[i] for i in indices[:r])
+while n:
+for i in reversed(range(r)):
+cycles[i] -= 1
+if cycles[i] == 0:
+indices[i:] = indices[i+1:] + indices[i:i+1]
+cycles[i] = n - i
+else:
+j = cycles[i]
+indices[i], indices[-j] = indices[-j], indices[i]
+yield tuple(pool[i] for i in indices[:r])
+break
+else:
+return
+def permutations2(iterable, r=None):
+'Pure python version shown in the docs'
+pool = tuple(iterable)
+n = len(pool)
+r = n if r is None else r
+for indices in product(range(n), repeat=r):
+if len(set(indices)) == r:
+yield tuple(pool[i] for i in indices)
+for n in range(7):
+values = [5*x-12 for x in range(n)]
+for r in range(n+1):
+result = list(permutations(values, r))
+self.assertEqual(len(result), fact(n) / fact(n-r))      # right number of perms
+self.assertEqual(len(result), len(set(result)))         # no repeats
+self.assertEqual(result, sorted(result))                # lexicographic order
+for p in result:
+self.assertEqual(len(p), r)                         # r-length permutations
+self.assertEqual(len(set(p)), r)                    # no duplicate elements
+self.assert_(all(e in values for e in p))           # elements taken from input iterable
+self.assertEqual(result, list(permutations1(values, r))) # matches first pure python version
+self.assertEqual(result, list(permutations2(values, r))) # matches first pure python version
+if r == n:
+self.assertEqual(result, list(permutations(values, None))) # test r as None
+self.assertEqual(result, list(permutations(values)))       # test default r
+# Test implementation detail:  tuple re-use
+self.assertEqual(len(set(map(id, permutations('abcde', 3)))), 1)
+self.assertNotEqual(len(set(map(id, list(permutations('abcde', 3))))), 1)
+def test_count(self):
+self.assertEqual(zip('abc',count()), [('a', 0), ('b', 1), ('c', 2)])
+self.assertEqual(zip('abc',count(3)), [('a', 3), ('b', 4), ('c', 5)])
+self.assertEqual(take(2, zip('abc',count(3))), [('a', 3), ('b', 4)])
+self.assertEqual(take(2, zip('abc',count(-1))), [('a', -1), ('b', 0)])
+self.assertEqual(take(2, zip('abc',count(-3))), [('a', -3), ('b', -2)])
+self.assertRaises(TypeError, count, 2, 3)
+self.assertRaises(TypeError, count, 'a')
+self.assertEqual(list(islice(count(maxsize-5), 10)), range(maxsize-5, maxsize+5))
+self.assertEqual(list(islice(count(-maxsize-5), 10)), range(-maxsize-5, -maxsize+5))
+c = count(3)
+self.assertEqual(repr(c), 'count(3)')
+c.next()
+self.assertEqual(repr(c), 'count(4)')
+c = count(-9)
+self.assertEqual(repr(c), 'count(-9)')
+c.next()
+self.assertEqual(c.next(), -8)
+for i in (-sys.maxint-5, -sys.maxint+5 ,-10, -1, 0, 10, sys.maxint-5, sys.maxint+5):
+# Test repr (ignoring the L in longs)
+r1 = repr(count(i)).replace('L', '')
+r2 = 'count(%r)'.__mod__(i).replace('L', '')
+self.assertEqual(r1, r2)
+def test_cycle(self):
+self.assertEqual(take(10, cycle('abc')), list('abcabcabca'))
+self.assertEqual(list(cycle('')), [])
+self.assertRaises(TypeError, cycle)
+self.assertRaises(TypeError, cycle, 5)
+self.assertEqual(list(islice(cycle(gen3()),10)), [0,1,2,0,1,2,0,1,2,0])
+def test_groupby(self):
+# Check whether it accepts arguments correctly
+self.assertEqual([], list(groupby([])))
+self.assertEqual([], list(groupby([], key=id)))
+self.assertRaises(TypeError, list, groupby('abc', []))
+self.assertRaises(TypeError, groupby, None)
+self.assertRaises(TypeError, groupby, 'abc', lambda x:x, 10)
+# Check normal input
+s = [(0, 10, 20), (0, 11,21), (0,12,21), (1,13,21), (1,14,22),
+(2,15,22), (3,16,23), (3,17,23)]
+dup = []
+for k, g in groupby(s, lambda r:r[0]):
+for elem in g:
+self.assertEqual(k, elem[0])
+dup.append(elem)
+self.assertEqual(s, dup)
+# Check nested case
+dup = []
+for k, g in groupby(s, lambda r:r[0]):
+for ik, ig in groupby(g, lambda r:r[2]):
+for elem in ig:
+self.assertEqual(k, elem[0])
+self.assertEqual(ik, elem[2])
+dup.append(elem)
+self.assertEqual(s, dup)
+# Check case where inner iterator is not used
+keys = [k for k, g in groupby(s, lambda r:r[0])]
+expectedkeys = set([r[0] for r in s])
+self.assertEqual(set(keys), expectedkeys)
+self.assertEqual(len(keys), len(expectedkeys))
+# Exercise pipes and filters style
+s = 'abracadabra'
+# sort s | uniq
+r = [k for k, g in groupby(sorted(s))]
+self.assertEqual(r, ['a', 'b', 'c', 'd', 'r'])
+# sort s | uniq -d
+r = [k for k, g in groupby(sorted(s)) if list(islice(g,1,2))]
+self.assertEqual(r, ['a', 'b', 'r'])
+# sort s | uniq -c
+r = [(len(list(g)), k) for k, g in groupby(sorted(s))]
+self.assertEqual(r, [(5, 'a'), (2, 'b'), (1, 'c'), (1, 'd'), (2, 'r')])
+# sort s | uniq -c | sort -rn | head -3
+r = sorted([(len(list(g)) , k) for k, g in groupby(sorted(s))], reverse=True)[:3]
+self.assertEqual(r, [(5, 'a'), (2, 'r'), (2, 'b')])
+# iter.next failure
+class ExpectedError(Exception):
+pass
+def delayed_raise(n=0):
+for i in range(n):
+yield 'yo'
+raise ExpectedError
+def gulp(iterable, keyp=None, func=list):
+return [func(g) for k, g in groupby(iterable, keyp)]
+# iter.next failure on outer object
+self.assertRaises(ExpectedError, gulp, delayed_raise(0))
+# iter.next failure on inner object
+self.assertRaises(ExpectedError, gulp, delayed_raise(1))
+# __cmp__ failure
+class DummyCmp:
+def __cmp__(self, dst):
+raise ExpectedError
+s = [DummyCmp(), DummyCmp(), None]
+# __cmp__ failure on outer object
+self.assertRaises(ExpectedError, gulp, s, func=id)
+# __cmp__ failure on inner object
+self.assertRaises(ExpectedError, gulp, s)
+# keyfunc failure
+def keyfunc(obj):
+if keyfunc.skip > 0:
+keyfunc.skip -= 1
+return obj
+else:
+raise ExpectedError
+# keyfunc failure on outer object
+keyfunc.skip = 0
+self.assertRaises(ExpectedError, gulp, [None], keyfunc)
+keyfunc.skip = 1
+self.assertRaises(ExpectedError, gulp, [None, None], keyfunc)
+def test_ifilter(self):
+self.assertEqual(list(ifilter(isEven, range(6))), [0,2,4])
+self.assertEqual(list(ifilter(None, [0,1,0,2,0])), [1,2])
+self.assertEqual(list(ifilter(bool, [0,1,0,2,0])), [1,2])
+self.assertEqual(take(4, ifilter(isEven, count())), [0,2,4,6])
+self.assertRaises(TypeError, ifilter)
+self.assertRaises(TypeError, ifilter, lambda x:x)
+self.assertRaises(TypeError, ifilter, lambda x:x, range(6), 7)
+self.assertRaises(TypeError, ifilter, isEven, 3)
+self.assertRaises(TypeError, ifilter(range(6), range(6)).next)
+def test_ifilterfalse(self):
+self.assertEqual(list(ifilterfalse(isEven, range(6))), [1,3,5])
+self.assertEqual(list(ifilterfalse(None, [0,1,0,2,0])), [0,0,0])
+self.assertEqual(list(ifilterfalse(bool, [0,1,0,2,0])), [0,0,0])
+self.assertEqual(take(4, ifilterfalse(isEven, count())), [1,3,5,7])
+self.assertRaises(TypeError, ifilterfalse)
+self.assertRaises(TypeError, ifilterfalse, lambda x:x)
+self.assertRaises(TypeError, ifilterfalse, lambda x:x, range(6), 7)
+self.assertRaises(TypeError, ifilterfalse, isEven, 3)
+self.assertRaises(TypeError, ifilterfalse(range(6), range(6)).next)
+def test_izip(self):
+ans = [(x,y) for x, y in izip('abc',count())]
+self.assertEqual(ans, [('a', 0), ('b', 1), ('c', 2)])
+self.assertEqual(list(izip('abc', range(6))), zip('abc', range(6)))
+self.assertEqual(list(izip('abcdef', range(3))), zip('abcdef', range(3)))
+self.assertEqual(take(3,izip('abcdef', count())), zip('abcdef', range(3)))
+self.assertEqual(list(izip('abcdef')), zip('abcdef'))
+self.assertEqual(list(izip()), zip())
+self.assertRaises(TypeError, izip, 3)
+self.assertRaises(TypeError, izip, range(3), 3)
+# Check tuple re-use (implementation detail)
+self.assertEqual([tuple(list(pair)) for pair in izip('abc', 'def')],
+zip('abc', 'def'))
+self.assertEqual([pair for pair in izip('abc', 'def')],
+zip('abc', 'def'))
+ids = map(id, izip('abc', 'def'))
+self.assertEqual(min(ids), max(ids))
+ids = map(id, list(izip('abc', 'def')))
+self.assertEqual(len(dict.fromkeys(ids)), len(ids))
+def test_iziplongest(self):
+for args in [
+['abc', range(6)],
+[range(6), 'abc'],
+[range(1000), range(2000,2100), range(3000,3050)],
+[range(1000), range(0), range(3000,3050), range(1200), range(1500)],
+[range(1000), range(0), range(3000,3050), range(1200), range(1500), range(0)],
+]:
+target = map(None, *args)
+self.assertEqual(list(izip_longest(*args)), target)
+self.assertEqual(list(izip_longest(*args, **{})), target)
+target = [tuple((e is None and 'X' or e) for e in t) for t in target]   # Replace None fills with 'X'
+self.assertEqual(list(izip_longest(*args, **dict(fillvalue='X'))), target)
+self.assertEqual(take(3,izip_longest('abcdef', count())), zip('abcdef', range(3))) # take 3 from infinite input
+self.assertEqual(list(izip_longest()), zip())
+self.assertEqual(list(izip_longest([])), zip([]))
+self.assertEqual(list(izip_longest('abcdef')), zip('abcdef'))
+self.assertEqual(list(izip_longest('abc', 'defg', **{})), map(None, 'abc', 'defg')) # empty keyword dict
+self.assertRaises(TypeError, izip_longest, 3)
+self.assertRaises(TypeError, izip_longest, range(3), 3)
+for stmt in [
+"izip_longest('abc', fv=1)",
+"izip_longest('abc', fillvalue=1, bogus_keyword=None)",
+]:
+try:
+eval(stmt, globals(), locals())
+except TypeError:
+pass
+else:
+self.fail('Did not raise Type in:  ' + stmt)
+# Check tuple re-use (implementation detail)
+self.assertEqual([tuple(list(pair)) for pair in izip_longest('abc', 'def')],
+zip('abc', 'def'))
+self.assertEqual([pair for pair in izip_longest('abc', 'def')],
+zip('abc', 'def'))
+ids = map(id, izip_longest('abc', 'def'))
+self.assertEqual(min(ids), max(ids))
+ids = map(id, list(izip_longest('abc', 'def')))
+self.assertEqual(len(dict.fromkeys(ids)), len(ids))
+def test_product(self):
+for args, result in [
+([], [()]),                     # zero iterables
+(['ab'], [('a',), ('b',)]),     # one iterable
+([range(2), range(3)], [(0,0), (0,1), (0,2), (1,0), (1,1), (1,2)]),     # two iterables
+([range(0), range(2), range(3)], []),           # first iterable with zero length
+([range(2), range(0), range(3)], []),           # middle iterable with zero length
+([range(2), range(3), range(0)], []),           # last iterable with zero length
+]:
+self.assertEqual(list(product(*args)), result)
+for r in range(4):
+self.assertEqual(list(product(*(args*r))),
+list(product(*args, **dict(repeat=r))))
+self.assertEqual(len(list(product(*[range(7)]*6))), 7**6)
+self.assertRaises(TypeError, product, range(6), None)
+def product1(*args, **kwds):
+pools = map(tuple, args) * kwds.get('repeat', 1)
+n = len(pools)
+if n == 0:
+yield ()
+return
+if any(len(pool) == 0 for pool in pools):
+return
+indices = [0] * n
+yield tuple(pool[i] for pool, i in zip(pools, indices))
+while 1:
+for i in reversed(range(n)):  # right to left
+if indices[i] == len(pools[i]) - 1:
+continue
+indices[i] += 1
+for j in range(i+1, n):
+indices[j] = 0
+yield tuple(pool[i] for pool, i in zip(pools, indices))
+break
+else:
+return
+def product2(*args, **kwds):
+'Pure python version used in docs'
+pools = map(tuple, args) * kwds.get('repeat', 1)
+result = [[]]
+for pool in pools:
+result = [x+[y] for x in result for y in pool]
+for prod in result:
+yield tuple(prod)
+argtypes = ['', 'abc', '', xrange(0), xrange(4), dict(a=1, b=2, c=3),
+set('abcdefg'), range(11), tuple(range(13))]
+for i in range(100):
+args = [random.choice(argtypes) for j in range(random.randrange(5))]
+expected_len = prod(map(len, args))
+self.assertEqual(len(list(product(*args))), expected_len)
+self.assertEqual(list(product(*args)), list(product1(*args)))
+self.assertEqual(list(product(*args)), list(product2(*args)))
+args = map(iter, args)
+self.assertEqual(len(list(product(*args))), expected_len)
+# Test implementation detail:  tuple re-use
+self.assertEqual(len(set(map(id, product('abc', 'def')))), 1)
+self.assertNotEqual(len(set(map(id, list(product('abc', 'def'))))), 1)
+def test_repeat(self):
+self.assertEqual(zip(xrange(3),repeat('a')),
+[(0, 'a'), (1, 'a'), (2, 'a')])
+self.assertEqual(list(repeat('a', 3)), ['a', 'a', 'a'])
+self.assertEqual(take(3, repeat('a')), ['a', 'a', 'a'])
+self.assertEqual(list(repeat('a', 0)), [])
+self.assertEqual(list(repeat('a', -3)), [])
+self.assertRaises(TypeError, repeat)
+self.assertRaises(TypeError, repeat, None, 3, 4)
+self.assertRaises(TypeError, repeat, None, 'a')
+r = repeat(1+0j)
+self.assertEqual(repr(r), 'repeat((1+0j))')
+r = repeat(1+0j, 5)
+self.assertEqual(repr(r), 'repeat((1+0j), 5)')
+list(r)
+self.assertEqual(repr(r), 'repeat((1+0j), 0)')
+def test_imap(self):
+self.assertEqual(list(imap(operator.pow, range(3), range(1,7))),
+[0**1, 1**2, 2**3])
+self.assertEqual(list(imap(None, 'abc', range(5))),
+[('a',0),('b',1),('c',2)])
+self.assertEqual(list(imap(None, 'abc', count())),
+[('a',0),('b',1),('c',2)])
+self.assertEqual(take(2,imap(None, 'abc', count())),
+[('a',0),('b',1)])
+self.assertEqual(list(imap(operator.pow, [])), [])
+self.assertRaises(TypeError, imap)
+self.assertRaises(TypeError, imap, operator.neg)
+self.assertRaises(TypeError, imap(10, range(5)).next)
+self.assertRaises(ValueError, imap(errfunc, [4], [5]).next)
+self.assertRaises(TypeError, imap(onearg, [4], [5]).next)
+def test_starmap(self):
+self.assertEqual(list(starmap(operator.pow, zip(range(3), range(1,7)))),
+[0**1, 1**2, 2**3])
+self.assertEqual(take(3, starmap(operator.pow, izip(count(), count(1)))),
+[0**1, 1**2, 2**3])
+self.assertEqual(list(starmap(operator.pow, [])), [])
+self.assertEqual(list(starmap(operator.pow, [iter([4,5])])), [4**5])
+self.assertRaises(TypeError, list, starmap(operator.pow, [None]))
+self.assertRaises(TypeError, starmap)
+self.assertRaises(TypeError, starmap, operator.pow, [(4,5)], 'extra')
+self.assertRaises(TypeError, starmap(10, [(4,5)]).next)
+self.assertRaises(ValueError, starmap(errfunc, [(4,5)]).next)
+self.assertRaises(TypeError, starmap(onearg, [(4,5)]).next)
+def test_islice(self):
+for args in [          # islice(args) should agree with range(args)
+(10, 20, 3),
+(10, 3, 20),
+(10, 20),
+(10, 3),
+(20,)
+]:
+self.assertEqual(list(islice(xrange(100), *args)), range(*args))
+for args, tgtargs in [  # Stop when seqn is exhausted
+((10, 110, 3), ((10, 100, 3))),
+((10, 110), ((10, 100))),
+((110,), (100,))
+]:
+self.assertEqual(list(islice(xrange(100), *args)), range(*tgtargs))
+# Test stop=None
+self.assertEqual(list(islice(xrange(10), None)), range(10))
+self.assertEqual(list(islice(xrange(10), None, None)), range(10))
+self.assertEqual(list(islice(xrange(10), None, None, None)), range(10))
+self.assertEqual(list(islice(xrange(10), 2, None)), range(2, 10))
+self.assertEqual(list(islice(xrange(10), 1, None, 2)), range(1, 10, 2))
+# Test number of items consumed     SF #1171417
+it = iter(range(10))
+self.assertEqual(list(islice(it, 3)), range(3))
+self.assertEqual(list(it), range(3, 10))
+# Test invalid arguments
+self.assertRaises(TypeError, islice, xrange(10))
+self.assertRaises(TypeError, islice, xrange(10), 1, 2, 3, 4)
+self.assertRaises(ValueError, islice, xrange(10), -5, 10, 1)
+self.assertRaises(ValueError, islice, xrange(10), 1, -5, -1)
+self.assertRaises(ValueError, islice, xrange(10), 1, 10, -1)
+self.assertRaises(ValueError, islice, xrange(10), 1, 10, 0)
+self.assertRaises(ValueError, islice, xrange(10), 'a')
+self.assertRaises(ValueError, islice, xrange(10), 'a', 1)
+self.assertRaises(ValueError, islice, xrange(10), 1, 'a')
+self.assertRaises(ValueError, islice, xrange(10), 'a', 1, 1)
+self.assertRaises(ValueError, islice, xrange(10), 1, 'a', 1)
+self.assertEqual(len(list(islice(count(), 1, 10, maxsize))), 1)
+def test_takewhile(self):
+data = [1, 3, 5, 20, 2, 4, 6, 8]
+underten = lambda x: x<10
+self.assertEqual(list(takewhile(underten, data)), [1, 3, 5])
+self.assertEqual(list(takewhile(underten, [])), [])
+self.assertRaises(TypeError, takewhile)
+self.assertRaises(TypeError, takewhile, operator.pow)
+self.assertRaises(TypeError, takewhile, operator.pow, [(4,5)], 'extra')
+self.assertRaises(TypeError, takewhile(10, [(4,5)]).next)
+self.assertRaises(ValueError, takewhile(errfunc, [(4,5)]).next)
+t = takewhile(bool, [1, 1, 1, 0, 0, 0])
+self.assertEqual(list(t), [1, 1, 1])
+self.assertRaises(StopIteration, t.next)
+def test_dropwhile(self):
+data = [1, 3, 5, 20, 2, 4, 6, 8]
+underten = lambda x: x<10
+self.assertEqual(list(dropwhile(underten, data)), [20, 2, 4, 6, 8])
+self.assertEqual(list(dropwhile(underten, [])), [])
+self.assertRaises(TypeError, dropwhile)
+self.assertRaises(TypeError, dropwhile, operator.pow)
+self.assertRaises(TypeError, dropwhile, operator.pow, [(4,5)], 'extra')
+self.assertRaises(TypeError, dropwhile(10, [(4,5)]).next)
+self.assertRaises(ValueError, dropwhile(errfunc, [(4,5)]).next)
+def test_tee(self):
+n = 200
+def irange(n):
+for i in xrange(n):
+yield i
+a, b = tee([])        # test empty iterator
+self.assertEqual(list(a), [])
+self.assertEqual(list(b), [])
+a, b = tee(irange(n)) # test 100% interleaved
+self.assertEqual(zip(a,b), zip(range(n),range(n)))
+a, b = tee(irange(n)) # test 0% interleaved
+self.assertEqual(list(a), range(n))
+self.assertEqual(list(b), range(n))
+a, b = tee(irange(n)) # test dealloc of leading iterator
+for i in xrange(100):
+self.assertEqual(a.next(), i)
+del a
+self.assertEqual(list(b), range(n))
+a, b = tee(irange(n)) # test dealloc of trailing iterator
+for i in xrange(100):
+self.assertEqual(a.next(), i)
+del b
+self.assertEqual(list(a), range(100, n))
+for j in xrange(5):   # test randomly interleaved
+order = [0]*n + [1]*n
+random.shuffle(order)
+lists = ([], [])
+its = tee(irange(n))
+for i in order:
+value = its[i].next()
+lists[i].append(value)
+self.assertEqual(lists[0], range(n))
+self.assertEqual(lists[1], range(n))
+# test argument format checking
+self.assertRaises(TypeError, tee)
+self.assertRaises(TypeError, tee, 3)
+self.assertRaises(TypeError, tee, [1,2], 'x')
+self.assertRaises(TypeError, tee, [1,2], 3, 'x')
+# tee object should be instantiable
+a, b = tee('abc')
+c = type(a)('def')
+self.assertEqual(list(c), list('def'))
+# test long-lagged and multi-way split
+a, b, c = tee(xrange(2000), 3)
+for i in xrange(100):
+self.assertEqual(a.next(), i)
+self.assertEqual(list(b), range(2000))
+self.assertEqual([c.next(), c.next()], range(2))
+self.assertEqual(list(a), range(100,2000))
+self.assertEqual(list(c), range(2,2000))
+# test values of n
+self.assertRaises(TypeError, tee, 'abc', 'invalid')
+self.assertRaises(ValueError, tee, [], -1)
+for n in xrange(5):
+result = tee('abc', n)
+self.assertEqual(type(result), tuple)
+self.assertEqual(len(result), n)
+self.assertEqual(map(list, result), [list('abc')]*n)
+# tee pass-through to copyable iterator
+a, b = tee('abc')
+c, d = tee(a)
+self.assert_(a is c)
+# test tee_new
+t1, t2 = tee('abc')
+tnew = type(t1)
+self.assertRaises(TypeError, tnew)
+self.assertRaises(TypeError, tnew, 10)
+t3 = tnew(t1)
+self.assert_(list(t1) == list(t2) == list(t3) == list('abc'))
+# test that tee objects are weak referencable
+a, b = tee(xrange(10))
+p = proxy(a)
+self.assertEqual(getattr(p, '__class__'), type(b))
+del a
+self.assertRaises(ReferenceError, getattr, p, '__class__')
+def test_StopIteration(self):
+self.assertRaises(StopIteration, izip().next)
+for f in (chain, cycle, izip, groupby):
+self.assertRaises(StopIteration, f([]).next)
+self.assertRaises(StopIteration, f(StopNow()).next)
+self.assertRaises(StopIteration, islice([], None).next)
+self.assertRaises(StopIteration, islice(StopNow(), None).next)
+p, q = tee([])
+self.assertRaises(StopIteration, p.next)
+self.assertRaises(StopIteration, q.next)
+p, q = tee(StopNow())
+self.assertRaises(StopIteration, p.next)
+self.assertRaises(StopIteration, q.next)
+self.assertRaises(StopIteration, repeat(None, 0).next)
+for f in (ifilter, ifilterfalse, imap, takewhile, dropwhile, starmap):
+self.assertRaises(StopIteration, f(lambda x:x, []).next)
+self.assertRaises(StopIteration, f(lambda x:x, StopNow()).next)
+class TestExamples(unittest.TestCase):
+def test_chain(self):
+self.assertEqual(''.join(chain('ABC', 'DEF')), 'ABCDEF')
+def test_chain_from_iterable(self):
+self.assertEqual(''.join(chain.from_iterable(['ABC', 'DEF'])), 'ABCDEF')
+def test_combinations(self):
+self.assertEqual(list(combinations('ABCD', 2)),
+[('A','B'), ('A','C'), ('A','D'), ('B','C'), ('B','D'), ('C','D')])
+self.assertEqual(list(combinations(range(4), 3)),
+[(0,1,2), (0,1,3), (0,2,3), (1,2,3)])
+def test_count(self):
+self.assertEqual(list(islice(count(10), 5)), [10, 11, 12, 13, 14])
+def test_cycle(self):
+self.assertEqual(list(islice(cycle('ABCD'), 12)), list('ABCDABCDABCD'))
+def test_dropwhile(self):
+self.assertEqual(list(dropwhile(lambda x: x<5, [1,4,6,4,1])), [6,4,1])
+def test_groupby(self):
+self.assertEqual([k for k, g in groupby('AAAABBBCCDAABBB')],
+list('ABCDAB'))
+self.assertEqual([(list(g)) for k, g in groupby('AAAABBBCCD')],
+[list('AAAA'), list('BBB'), list('CC'), list('D')])
+def test_ifilter(self):
+self.assertEqual(list(ifilter(lambda x: x%2, range(10))), [1,3,5,7,9])
+def test_ifilterfalse(self):
+self.assertEqual(list(ifilterfalse(lambda x: x%2, range(10))), [0,2,4,6,8])
+def test_imap(self):
+self.assertEqual(list(imap(pow, (2,3,10), (5,2,3))), [32, 9, 1000])
+def test_islice(self):
+self.assertEqual(list(islice('ABCDEFG', 2)), list('AB'))
+self.assertEqual(list(islice('ABCDEFG', 2, 4)), list('CD'))
+self.assertEqual(list(islice('ABCDEFG', 2, None)), list('CDEFG'))
+self.assertEqual(list(islice('ABCDEFG', 0, None, 2)), list('ACEG'))
+def test_izip(self):
+self.assertEqual(list(izip('ABCD', 'xy')), [('A', 'x'), ('B', 'y')])
+def test_izip_longest(self):
+self.assertEqual(list(izip_longest('ABCD', 'xy', fillvalue='-')),
+[('A', 'x'), ('B', 'y'), ('C', '-'), ('D', '-')])
+def test_permutations(self):
+self.assertEqual(list(permutations('ABCD', 2)),
+map(tuple, 'AB AC AD BA BC BD CA CB CD DA DB DC'.split()))
+self.assertEqual(list(permutations(range(3))),
+[(0,1,2), (0,2,1), (1,0,2), (1,2,0), (2,0,1), (2,1,0)])
+def test_product(self):
+self.assertEqual(list(product('ABCD', 'xy')),
+map(tuple, 'Ax Ay Bx By Cx Cy Dx Dy'.split()))
+self.assertEqual(list(product(range(2), repeat=3)),
+[(0,0,0), (0,0,1), (0,1,0), (0,1,1),
+(1,0,0), (1,0,1), (1,1,0), (1,1,1)])
+def test_repeat(self):
+self.assertEqual(list(repeat(10, 3)), [10, 10, 10])
+def test_stapmap(self):
+self.assertEqual(list(starmap(pow, [(2,5), (3,2), (10,3)])),
+[32, 9, 1000])
+def test_takewhile(self):
+self.assertEqual(list(takewhile(lambda x: x<5, [1,4,6,4,1])), [1,4])
+class TestGC(unittest.TestCase):
+def makecycle(self, iterator, container):
+container.append(iterator)
+iterator.next()
+del container, iterator
+def test_chain(self):
+a = []
+self.makecycle(chain(a), a)
+def test_chain_from_iterable(self):
+a = []
+self.makecycle(chain.from_iterable([a]), a)
+def test_combinations(self):
+a = []
+self.makecycle(combinations([1,2,a,3], 3), a)
+def test_cycle(self):
+a = []
+self.makecycle(cycle([a]*2), a)
+def test_dropwhile(self):
+a = []
+self.makecycle(dropwhile(bool, [0, a, a]), a)
+def test_groupby(self):
+a = []
+self.makecycle(groupby([a]*2, lambda x:x), a)
+def test_issue2246(self):
+# Issue 2246 -- the _grouper iterator was not included in GC
+n = 10
+keyfunc = lambda x: x
+for i, j in groupby(xrange(n), key=keyfunc):
+keyfunc.__dict__.setdefault('x',[]).append(j)
+def test_ifilter(self):
+a = []
+self.makecycle(ifilter(lambda x:True, [a]*2), a)
+def test_ifilterfalse(self):
+a = []
+self.makecycle(ifilterfalse(lambda x:False, a), a)
+def test_izip(self):
+a = []
+self.makecycle(izip([a]*2, [a]*3), a)
+def test_izip_longest(self):
+a = []
+self.makecycle(izip_longest([a]*2, [a]*3), a)
+b = [a, None]
+self.makecycle(izip_longest([a]*2, [a]*3, fillvalue=b), a)
+def test_imap(self):
+a = []
+self.makecycle(imap(lambda x:x, [a]*2), a)
+def test_islice(self):
+a = []
+self.makecycle(islice([a]*2, None), a)
+def test_permutations(self):
+a = []
+self.makecycle(permutations([1,2,a,3], 3), a)
+def test_product(self):
+a = []
+self.makecycle(product([1,2,a,3], repeat=3), a)
+def test_repeat(self):
+a = []
+self.makecycle(repeat(a), a)
+def test_starmap(self):
+a = []
+self.makecycle(starmap(lambda *t: t, [(a,a)]*2), a)
+def test_takewhile(self):
+a = []
+self.makecycle(takewhile(bool, [1, 0, a, a]), a)
+def R(seqn):
+'Regular generator'
+for i in seqn:
+yield i
+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 N:
+'Iterator missing next()'
+def __init__(self, seqn):
+self.seqn = seqn
+self.i = 0
+def __iter__(self):
+return self
+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 S:
+'Test immediate stop'
+def __init__(self, seqn):
+pass
+def __iter__(self):
+return self
+def next(self):
+raise StopIteration
+def L(seqn):
+'Test multiple tiers of iterators'
+return chain(imap(lambda x:x, R(Ig(G(seqn)))))
+class TestVariousIteratorArgs(unittest.TestCase):
+def test_chain(self):
+for s in ("123", "", range(1000), ('do', 1.2), xrange(2000,2200,5)):
+for g in (G, I, Ig, S, L, R):
+self.assertEqual(list(chain(g(s))), list(g(s)))
+self.assertEqual(list(chain(g(s), g(s))), list(g(s))+list(g(s)))
+self.assertRaises(TypeError, list, chain(X(s)))
+self.assertRaises(TypeError, list, chain(N(s)))
+self.assertRaises(ZeroDivisionError, list, chain(E(s)))
+def test_product(self):
+for s in ("123", "", range(1000), ('do', 1.2), xrange(2000,2200,5)):
+self.assertRaises(TypeError, product, X(s))
+self.assertRaises(TypeError, product, N(s))
+self.assertRaises(ZeroDivisionError, product, E(s))
+def test_cycle(self):
+for s in ("123", "", range(1000), ('do', 1.2), xrange(2000,2200,5)):
+for g in (G, I, Ig, S, L, R):
+tgtlen = len(s) * 3
+expected = list(g(s))*3
+actual = list(islice(cycle(g(s)), tgtlen))
+self.assertEqual(actual, expected)
+self.assertRaises(TypeError, cycle, X(s))
+self.assertRaises(TypeError, list, cycle(N(s)))
+self.assertRaises(ZeroDivisionError, list, cycle(E(s)))
+def test_groupby(self):
+for s in (range(10), range(0), range(1000), (7,11), xrange(2000,2200,5)):
+for g in (G, I, Ig, S, L, R):
+self.assertEqual([k for k, sb in groupby(g(s))], list(g(s)))
+self.assertRaises(TypeError, groupby, X(s))
+self.assertRaises(TypeError, list, groupby(N(s)))
+self.assertRaises(ZeroDivisionError, list, groupby(E(s)))
+def test_ifilter(self):
+for s in (range(10), range(0), range(1000), (7,11), xrange(2000,2200,5)):
+for g in (G, I, Ig, S, L, R):
+self.assertEqual(list(ifilter(isEven, g(s))), filter(isEven, g(s)))
+self.assertRaises(TypeError, ifilter, isEven, X(s))
+self.assertRaises(TypeError, list, ifilter(isEven, N(s)))
+self.assertRaises(ZeroDivisionError, list, ifilter(isEven, E(s)))
+def test_ifilterfalse(self):
+for s in (range(10), range(0), range(1000), (7,11), xrange(2000,2200,5)):
+for g in (G, I, Ig, S, L, R):
+self.assertEqual(list(ifilterfalse(isEven, g(s))), filter(isOdd, g(s)))
+self.assertRaises(TypeError, ifilterfalse, isEven, X(s))
+self.assertRaises(TypeError, list, ifilterfalse(isEven, N(s)))
+self.assertRaises(ZeroDivisionError, list, ifilterfalse(isEven, E(s)))
+def test_izip(self):
+for s in ("123", "", range(1000), ('do', 1.2), xrange(2000,2200,5)):
+for g in (G, I, Ig, S, L, R):
+self.assertEqual(list(izip(g(s))), zip(g(s)))
+self.assertEqual(list(izip(g(s), g(s))), zip(g(s), g(s)))
+self.assertRaises(TypeError, izip, X(s))
+self.assertRaises(TypeError, list, izip(N(s)))
+self.assertRaises(ZeroDivisionError, list, izip(E(s)))
+def test_iziplongest(self):
+for s in ("123", "", range(1000), ('do', 1.2), xrange(2000,2200,5)):
+for g in (G, I, Ig, S, L, R):
+self.assertEqual(list(izip_longest(g(s))), zip(g(s)))
+self.assertEqual(list(izip_longest(g(s), g(s))), zip(g(s), g(s)))
+self.assertRaises(TypeError, izip_longest, X(s))
+self.assertRaises(TypeError, list, izip_longest(N(s)))
+self.assertRaises(ZeroDivisionError, list, izip_longest(E(s)))
+def test_imap(self):
+for s in (range(10), range(0), range(100), (7,11), xrange(20,50,5)):
+for g in (G, I, Ig, S, L, R):
+self.assertEqual(list(imap(onearg, g(s))), map(onearg, g(s)))
+self.assertEqual(list(imap(operator.pow, g(s), g(s))), map(operator.pow, g(s), g(s)))
+self.assertRaises(TypeError, imap, onearg, X(s))
+self.assertRaises(TypeError, list, imap(onearg, N(s)))
+self.assertRaises(ZeroDivisionError, list, imap(onearg, E(s)))
+def test_islice(self):
+for s in ("12345", "", range(1000), ('do', 1.2), xrange(2000,2200,5)):
+for g in (G, I, Ig, S, L, R):
+self.assertEqual(list(islice(g(s),1,None,2)), list(g(s))[1::2])
+self.assertRaises(TypeError, islice, X(s), 10)
+self.assertRaises(TypeError, list, islice(N(s), 10))
+self.assertRaises(ZeroDivisionError, list, islice(E(s), 10))
+def test_starmap(self):
+for s in (range(10), range(0), range(100), (7,11), xrange(20,50,5)):
+for g in (G, I, Ig, S, L, R):
+ss = zip(s, s)
+self.assertEqual(list(starmap(operator.pow, g(ss))), map(operator.pow, g(s), g(s)))
+self.assertRaises(TypeError, starmap, operator.pow, X(ss))
+self.assertRaises(TypeError, list, starmap(operator.pow, N(ss)))
+self.assertRaises(ZeroDivisionError, list, starmap(operator.pow, E(ss)))
+def test_takewhile(self):
+for s in (range(10), range(0), range(1000), (7,11), xrange(2000,2200,5)):
+for g in (G, I, Ig, S, L, R):
+tgt = []
+for elem in g(s):
+if not isEven(elem): break
+tgt.append(elem)
+self.assertEqual(list(takewhile(isEven, g(s))), tgt)
+self.assertRaises(TypeError, takewhile, isEven, X(s))
+self.assertRaises(TypeError, list, takewhile(isEven, N(s)))
+self.assertRaises(ZeroDivisionError, list, takewhile(isEven, E(s)))
+def test_dropwhile(self):
+for s in (range(10), range(0), range(1000), (7,11), xrange(2000,2200,5)):
+for g in (G, I, Ig, S, L, R):
+tgt = []
+for elem in g(s):
+if not tgt and isOdd(elem): continue
+tgt.append(elem)
+self.assertEqual(list(dropwhile(isOdd, g(s))), tgt)
+self.assertRaises(TypeError, dropwhile, isOdd, X(s))
+self.assertRaises(TypeError, list, dropwhile(isOdd, N(s)))
+self.assertRaises(ZeroDivisionError, list, dropwhile(isOdd, E(s)))
+def test_tee(self):
+for s in ("123", "", range(1000), ('do', 1.2), xrange(2000,2200,5)):
+for g in (G, I, Ig, S, L, R):
+it1, it2 = tee(g(s))
+self.assertEqual(list(it1), list(g(s)))
+self.assertEqual(list(it2), list(g(s)))
+self.assertRaises(TypeError, tee, X(s))
+self.assertRaises(TypeError, list, tee(N(s))[0])
+self.assertRaises(ZeroDivisionError, list, tee(E(s))[0])
+class LengthTransparency(unittest.TestCase):
+def test_repeat(self):
+from test.test_iterlen import len
+self.assertEqual(len(repeat(None, 50)), 50)
+self.assertRaises(TypeError, len, repeat(None))
+class RegressionTests(unittest.TestCase):
+def test_sf_793826(self):
+# Fix Armin Rigo's successful efforts to wreak havoc
+def mutatingtuple(tuple1, f, tuple2):
+# this builds a tuple t which is a copy of tuple1,
+# then calls f(t), then mutates t to be equal to tuple2
+# (needs len(tuple1) == len(tuple2)).
+def g(value, first=[1]):
+if first:
+del first[:]
+f(z.next())
+return value
+items = list(tuple2)
+items[1:1] = list(tuple1)
+gen = imap(g, items)
+z = izip(*[gen]*len(tuple1))
+z.next()
+def f(t):
+global T
+T = t
+first[:] = list(T)
+first = []
+mutatingtuple((1,2,3), f, (4,5,6))
+second = list(T)
+self.assertEqual(first, second)
+def test_sf_950057(self):
+# Make sure that chain() and cycle() catch exceptions immediately
+# rather than when shifting between input sources
+def gen1():
+hist.append(0)
+yield 1
+hist.append(1)
+raise AssertionError
+hist.append(2)
+def gen2(x):
+hist.append(3)
+yield 2
+hist.append(4)
+if x:
+raise StopIteration
+hist = []
+self.assertRaises(AssertionError, list, chain(gen1(), gen2(False)))
+self.assertEqual(hist, [0,1])
+hist = []
+self.assertRaises(AssertionError, list, chain(gen1(), gen2(True)))
+self.assertEqual(hist, [0,1])
+hist = []
+self.assertRaises(AssertionError, list, cycle(gen1()))
+self.assertEqual(hist, [0,1])
+class SubclassWithKwargsTest(unittest.TestCase):
+def test_keywords_in_subclass(self):
+# count is not subclassable...
+for cls in (repeat, izip, ifilter, ifilterfalse, chain, imap,
+starmap, islice, takewhile, dropwhile, cycle):
+class Subclass(cls):
+def __init__(self, newarg=None, *args):
+cls.__init__(self, *args)
+try:
+Subclass(newarg=1)
+except TypeError, err:
+# we expect type errors because of wrong argument count
+self.failIf("does not take keyword arguments" in err.args[0])
+libreftest = """ Doctest for examples in the library reference: libitertools.tex
+>>> amounts = [120.15, 764.05, 823.14]
+>>> for checknum, amount in izip(count(1200), amounts):
+...     print 'Check %d is for $%.2f' % (checknum, amount)
+...
+Check 1200 is for $120.15
+Check 1201 is for $764.05
+Check 1202 is for $823.14
+>>> import operator
+>>> for cube in imap(operator.pow, xrange(1,4), repeat(3)):
+...    print cube
+...
+1
+8
+27
+>>> reportlines = ['EuroPython', 'Roster', '', 'alex', '', 'laura', '', 'martin', '', 'walter', '', 'samuele']
+>>> for name in islice(reportlines, 3, None, 2):
+...    print name.title()
+...
+Alex
+Laura
+Martin
+Walter
+Samuele
+>>> from operator import itemgetter
+>>> d = dict(a=1, b=2, c=1, d=2, e=1, f=2, g=3)
+>>> di = sorted(sorted(d.iteritems()), key=itemgetter(1))
+>>> for k, g in groupby(di, itemgetter(1)):
+...     print k, map(itemgetter(0), g)
+...
+1 ['a', 'c', 'e']
+2 ['b', 'd', 'f']
+3 ['g']
+# Find runs of consecutive numbers using groupby.  The key to the solution
+# is differencing with a range so that consecutive numbers all appear in
+# same group.
+>>> data = [ 1,  4,5,6, 10, 15,16,17,18, 22, 25,26,27,28]
+>>> for k, g in groupby(enumerate(data), lambda (i,x):i-x):
+...     print map(operator.itemgetter(1), g)
+...
+[1]
+[4, 5, 6]
+[10]
+[15, 16, 17, 18]
+[22]
+[25, 26, 27, 28]
+>>> def take(n, iterable):
+...     "Return first n items of the iterable as a list"
+...     return list(islice(iterable, n))
+>>> def enumerate(iterable, start=0):
+...     return izip(count(start), iterable)
+>>> def tabulate(function, start=0):
+...     "Return function(0), function(1), ..."
+...     return imap(function, count(start))
+>>> def nth(iterable, n):
+...     "Returns the nth item or empty list"
+...     return list(islice(iterable, n, n+1))
+>>> def quantify(iterable, pred=bool):
+...     "Count how many times the predicate is true"
+...     return sum(imap(pred, iterable))
+>>> def padnone(iterable):
+...     "Returns the sequence elements and then returns None indefinitely"
+...     return chain(iterable, repeat(None))
+>>> def ncycles(iterable, n):
+...     "Returns the seqeuence elements n times"
+...     return chain(*repeat(iterable, n))
+>>> def dotproduct(vec1, vec2):
+...     return sum(imap(operator.mul, vec1, vec2))
+>>> def flatten(listOfLists):
+...     return list(chain.from_iterable(listOfLists))
+>>> def repeatfunc(func, times=None, *args):
+...     "Repeat calls to func with specified arguments."
+...     "   Example:  repeatfunc(random.random)"
+...     if times is None:
+...         return starmap(func, repeat(args))
+...     else:
+...         return starmap(func, repeat(args, times))
+>>> def pairwise(iterable):
+...     "s -> (s0,s1), (s1,s2), (s2, s3), ..."
+...     a, b = tee(iterable)
+...     for elem in b:
+...         break
+...     return izip(a, b)
+>>> def grouper(n, iterable, fillvalue=None):
+...     "grouper(3, 'ABCDEFG', 'x') --> ABC DEF Gxx"
+...     args = [iter(iterable)] * n
+...     return izip_longest(fillvalue=fillvalue, *args)
+>>> def roundrobin(*iterables):
+...     "roundrobin('ABC', 'D', 'EF') --> A D E B F C"
+...     # Recipe credited to George Sakkis
+...     pending = len(iterables)
+...     nexts = cycle(iter(it).next for it in iterables)
+...     while pending:
+...         try:
+...             for next in nexts:
+...                 yield next()
+...         except StopIteration:
+...             pending -= 1
+...             nexts = cycle(islice(nexts, pending))
+>>> def powerset(iterable):
+...     "powerset('ab') --> set([]), set(['a']), set(['b']), set(['a', 'b'])"
+...     # Recipe credited to Eric Raymond
+...     pairs = [(2**i, x) for i, x in enumerate(iterable)]
+...     for n in xrange(2**len(pairs)):
+...         yield set(x for m, x in pairs if m&n)
+>>> def compress(data, selectors):
+...     "compress('ABCDEF', [1,0,1,0,1,1]) --> A C E F"
+...     return (d for d, s in izip(data, selectors) if s)
+>>> def combinations_with_replacement(iterable, r):
+...     "combinations_with_replacement('ABC', 3) --> AA AB AC BB BC CC"
+...     pool = tuple(iterable)
+...     n = len(pool)
+...     indices = [0] * r
+...     yield tuple(pool[i] for i in indices)
+...     while 1:
+...         for i in reversed(range(r)):
+...             if indices[i] != n - 1:
+...                 break
+...         else:
+...             return
+...         indices[i:] = [indices[i] + 1] * (r - i)
+...         yield tuple(pool[i] for i in indices)
+This is not part of the examples but it tests to make sure the definitions
+perform as purported.
+>>> take(10, count())
+[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+>>> list(enumerate('abc'))
+[(0, 'a'), (1, 'b'), (2, 'c')]
+>>> list(islice(tabulate(lambda x: 2*x), 4))
+[0, 2, 4, 6]
+>>> nth('abcde', 3)
+['d']
+>>> quantify(xrange(99), lambda x: x%2==0)
+50
+>>> a = [[1, 2, 3], [4, 5, 6]]
+>>> flatten(a)
+[1, 2, 3, 4, 5, 6]
+>>> list(repeatfunc(pow, 5, 2, 3))
+[8, 8, 8, 8, 8]
+>>> import random
+>>> take(5, imap(int, repeatfunc(random.random)))
+[0, 0, 0, 0, 0]
+>>> list(pairwise('abcd'))
+[('a', 'b'), ('b', 'c'), ('c', 'd')]
+>>> list(pairwise([]))
+[]
+>>> list(pairwise('a'))
+[]
+>>> list(islice(padnone('abc'), 0, 6))
+['a', 'b', 'c', None, None, None]
+>>> list(ncycles('abc', 3))
+['a', 'b', 'c', 'a', 'b', 'c', 'a', 'b', 'c']
+>>> dotproduct([1,2,3], [4,5,6])
+32
+>>> list(grouper(3, 'abcdefg', 'x'))
+[('a', 'b', 'c'), ('d', 'e', 'f'), ('g', 'x', 'x')]
+>>> list(roundrobin('abc', 'd', 'ef'))
+['a', 'd', 'e', 'b', 'f', 'c']
+>>> map(sorted, powerset('ab'))
+[[], ['a'], ['b'], ['a', 'b']]
+>>> list(compress('abcdef', [1,0,1,0,1,1]))
+['a', 'c', 'e', 'f']
+>>> list(combinations_with_replacement('abc', 2))
+[('a', 'a'), ('a', 'b'), ('a', 'c'), ('b', 'b'), ('b', 'c'), ('c', 'c')]
+"""
+__test__ = {'libreftest' : libreftest}
+def test_main(verbose=None):
+test_classes = (TestBasicOps, TestVariousIteratorArgs, TestGC,
+RegressionTests, LengthTransparency,
+SubclassWithKwargsTest, TestExamples)
+test_support.run_unittest(*test_classes)
+# verify reference counting
+if verbose and hasattr(sys, "gettotalrefcount"):
+import gc
+counts = [None] * 5
+for i in xrange(len(counts)):
+test_support.run_unittest(*test_classes)
+gc.collect()
+counts[i] = sys.gettotalrefcount()
+print counts
+# doctest the examples in the library reference
+test_support.run_doctest(sys.modules[__name__], verbose)
+if __name__ == "__main__":
+test_main(verbose=True)