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cpython/Lib/test/test_iter.py
Guido van Rossum 97c1adf393 Anti-registration of various ABC methods. 
- Issue #25958: Support "anti-registration" of special methods from
  various ABCs, like __hash__, __iter__ or __len__.  All these (and
  several more) can be set to None in an implementation class and the
  behavior will be as if the method is not defined at all.
  (Previously, this mechanism existed only for __hash__, to make
  mutable classes unhashable.)  Code contributed by Andrew Barnert and
  Ivan Levkivskyi.
2016-08-18 09:22:23 -07:00

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# Test iterators.
import sys
import unittest
from test.support import run_unittest, TESTFN, unlink, cpython_only
from test.support import check_free_after_iterating
import pickle
import collections.abc
# Test result of triple loop (too big to inline)
TRIPLETS = [(0, 0, 0), (0, 0, 1), (0, 0, 2),
(0, 1, 0), (0, 1, 1), (0, 1, 2),
(0, 2, 0), (0, 2, 1), (0, 2, 2),
(1, 0, 0), (1, 0, 1), (1, 0, 2),
(1, 1, 0), (1, 1, 1), (1, 1, 2),
(1, 2, 0), (1, 2, 1), (1, 2, 2),
(2, 0, 0), (2, 0, 1), (2, 0, 2),
(2, 1, 0), (2, 1, 1), (2, 1, 2),
(2, 2, 0), (2, 2, 1), (2, 2, 2)]
# Helper classes
class BasicIterClass:
def __init__(self, n):
self.n = n
self.i = 0
def __next__(self):
res = self.i
if res >= self.n:
raise StopIteration
self.i = res + 1
return res
def __iter__(self):
return self
class IteratingSequenceClass:
def __init__(self, n):
self.n = n
def __iter__(self):
return BasicIterClass(self.n)
class SequenceClass:
def __init__(self, n):
self.n = n
def __getitem__(self, i):
if 0 <= i < self.n:
return i
else:
raise IndexError
class UnlimitedSequenceClass:
def __getitem__(self, i):
return i
class DefaultIterClass:
pass
class NoIterClass:
def __getitem__(self, i):
return i
__iter__ = None
# Main test suite
class TestCase(unittest.TestCase):
# Helper to check that an iterator returns a given sequence
def check_iterator(self, it, seq, pickle=True):
if pickle:
self.check_pickle(it, seq)
res = []
while 1:
try:
val = next(it)
except StopIteration:
break
res.append(val)
self.assertEqual(res, seq)
# Helper to check that a for loop generates a given sequence
def check_for_loop(self, expr, seq, pickle=True):
if pickle:
self.check_pickle(iter(expr), seq)
res = []
for val in expr:
res.append(val)
self.assertEqual(res, seq)
# Helper to check picklability
def check_pickle(self, itorg, seq):
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
d = pickle.dumps(itorg, proto)
it = pickle.loads(d)
# Cannot assert type equality because dict iterators unpickle as list
# iterators.
# self.assertEqual(type(itorg), type(it))
self.assertTrue(isinstance(it, collections.abc.Iterator))
self.assertEqual(list(it), seq)
it = pickle.loads(d)
try:
next(it)
except StopIteration:
continue
d = pickle.dumps(it, proto)
it = pickle.loads(d)
self.assertEqual(list(it), seq[1:])
# Test basic use of iter() function
def test_iter_basic(self):
self.check_iterator(iter(range(10)), list(range(10)))
# Test that iter(iter(x)) is the same as iter(x)
def test_iter_idempotency(self):
seq = list(range(10))
it = iter(seq)
it2 = iter(it)
self.assertTrue(it is it2)
# Test that for loops over iterators work
def test_iter_for_loop(self):
self.check_for_loop(iter(range(10)), list(range(10)))
# Test several independent iterators over the same list
def test_iter_independence(self):
seq = range(3)
res = []
for i in iter(seq):
for j in iter(seq):
for k in iter(seq):
res.append((i, j, k))
self.assertEqual(res, TRIPLETS)
# Test triple list comprehension using iterators
def test_nested_comprehensions_iter(self):
seq = range(3)
res = [(i, j, k)
for i in iter(seq) for j in iter(seq) for k in iter(seq)]
self.assertEqual(res, TRIPLETS)
# Test triple list comprehension without iterators
def test_nested_comprehensions_for(self):
seq = range(3)
res = [(i, j, k) for i in seq for j in seq for k in seq]
self.assertEqual(res, TRIPLETS)
# Test a class with __iter__ in a for loop
def test_iter_class_for(self):
self.check_for_loop(IteratingSequenceClass(10), list(range(10)))
# Test a class with __iter__ with explicit iter()
def test_iter_class_iter(self):
self.check_iterator(iter(IteratingSequenceClass(10)), list(range(10)))
# Test for loop on a sequence class without __iter__
def test_seq_class_for(self):
self.check_for_loop(SequenceClass(10), list(range(10)))
# Test iter() on a sequence class without __iter__
def test_seq_class_iter(self):
self.check_iterator(iter(SequenceClass(10)), list(range(10)))
def test_mutating_seq_class_iter_pickle(self):
orig = SequenceClass(5)
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
# initial iterator
itorig = iter(orig)
d = pickle.dumps((itorig, orig), proto)
it, seq = pickle.loads(d)
seq.n = 7
self.assertIs(type(it), type(itorig))
self.assertEqual(list(it), list(range(7)))
# running iterator
next(itorig)
d = pickle.dumps((itorig, orig), proto)
it, seq = pickle.loads(d)
seq.n = 7
self.assertIs(type(it), type(itorig))
self.assertEqual(list(it), list(range(1, 7)))
# empty iterator
for i in range(1, 5):
next(itorig)
d = pickle.dumps((itorig, orig), proto)
it, seq = pickle.loads(d)
seq.n = 7
self.assertIs(type(it), type(itorig))
self.assertEqual(list(it), list(range(5, 7)))
# exhausted iterator
self.assertRaises(StopIteration, next, itorig)
d = pickle.dumps((itorig, orig), proto)
it, seq = pickle.loads(d)
seq.n = 7
self.assertTrue(isinstance(it, collections.abc.Iterator))
self.assertEqual(list(it), [])
def test_mutating_seq_class_exhausted_iter(self):
a = SequenceClass(5)
exhit = iter(a)
empit = iter(a)
for x in exhit: # exhaust the iterator
next(empit) # not exhausted
a.n = 7
self.assertEqual(list(exhit), [])
self.assertEqual(list(empit), [5, 6])
self.assertEqual(list(a), [0, 1, 2, 3, 4, 5, 6])
# Test a new_style class with __iter__ but no next() method
def test_new_style_iter_class(self):
class IterClass(object):
def __iter__(self):
return self
self.assertRaises(TypeError, iter, IterClass())
# Test two-argument iter() with callable instance
def test_iter_callable(self):
class C:
def __init__(self):
self.i = 0
def __call__(self):
i = self.i
self.i = i + 1
if i > 100:
raise IndexError # Emergency stop
return i
self.check_iterator(iter(C(), 10), list(range(10)), pickle=False)
# Test two-argument iter() with function
def test_iter_function(self):
def spam(state=[0]):
i = state[0]
state[0] = i+1
return i
self.check_iterator(iter(spam, 10), list(range(10)), pickle=False)
# Test two-argument iter() with function that raises StopIteration
def test_iter_function_stop(self):
def spam(state=[0]):
i = state[0]
if i == 10:
raise StopIteration
state[0] = i+1
return i
self.check_iterator(iter(spam, 20), list(range(10)), pickle=False)
# Test exception propagation through function iterator
def test_exception_function(self):
def spam(state=[0]):
i = state[0]
state[0] = i+1
if i == 10:
raise RuntimeError
return i
res = []
try:
for x in iter(spam, 20):
res.append(x)
except RuntimeError:
self.assertEqual(res, list(range(10)))
else:
self.fail("should have raised RuntimeError")
# Test exception propagation through sequence iterator
def test_exception_sequence(self):
class MySequenceClass(SequenceClass):
def __getitem__(self, i):
if i == 10:
raise RuntimeError
return SequenceClass.__getitem__(self, i)
res = []
try:
for x in MySequenceClass(20):
res.append(x)
except RuntimeError:
self.assertEqual(res, list(range(10)))
else:
self.fail("should have raised RuntimeError")
# Test for StopIteration from __getitem__
def test_stop_sequence(self):
class MySequenceClass(SequenceClass):
def __getitem__(self, i):
if i == 10:
raise StopIteration
return SequenceClass.__getitem__(self, i)
self.check_for_loop(MySequenceClass(20), list(range(10)), pickle=False)
# Test a big range
def test_iter_big_range(self):
self.check_for_loop(iter(range(10000)), list(range(10000)))
# Test an empty list
def test_iter_empty(self):
self.check_for_loop(iter([]), [])
# Test a tuple
def test_iter_tuple(self):
self.check_for_loop(iter((0,1,2,3,4,5,6,7,8,9)), list(range(10)))
# Test a range
def test_iter_range(self):
self.check_for_loop(iter(range(10)), list(range(10)))
# Test a string
def test_iter_string(self):
self.check_for_loop(iter("abcde"), ["a", "b", "c", "d", "e"])
# Test a directory
def test_iter_dict(self):
dict = {}
for i in range(10):
dict[i] = None
self.check_for_loop(dict, list(dict.keys()))
# Test a file
def test_iter_file(self):
f = open(TESTFN, "w")
try:
for i in range(5):
f.write("%d\n" % i)
finally:
f.close()
f = open(TESTFN, "r")
try:
self.check_for_loop(f, ["0\n", "1\n", "2\n", "3\n", "4\n"], pickle=False)
self.check_for_loop(f, [], pickle=False)
finally:
f.close()
try:
unlink(TESTFN)
except OSError:
pass
# Test list()'s use of iterators.
def test_builtin_list(self):
self.assertEqual(list(SequenceClass(5)), list(range(5)))
self.assertEqual(list(SequenceClass(0)), [])
self.assertEqual(list(()), [])
d = {"one": 1, "two": 2, "three": 3}
self.assertEqual(list(d), list(d.keys()))
self.assertRaises(TypeError, list, list)
self.assertRaises(TypeError, list, 42)
f = open(TESTFN, "w")
try:
for i in range(5):
f.write("%d\n" % i)
finally:
f.close()
f = open(TESTFN, "r")
try:
self.assertEqual(list(f), ["0\n", "1\n", "2\n", "3\n", "4\n"])
f.seek(0, 0)
self.assertEqual(list(f),
["0\n", "1\n", "2\n", "3\n", "4\n"])
finally:
f.close()
try:
unlink(TESTFN)
except OSError:
pass
# Test tuples()'s use of iterators.
def test_builtin_tuple(self):
self.assertEqual(tuple(SequenceClass(5)), (0, 1, 2, 3, 4))
self.assertEqual(tuple(SequenceClass(0)), ())
self.assertEqual(tuple([]), ())
self.assertEqual(tuple(()), ())
self.assertEqual(tuple("abc"), ("a", "b", "c"))
d = {"one": 1, "two": 2, "three": 3}
self.assertEqual(tuple(d), tuple(d.keys()))
self.assertRaises(TypeError, tuple, list)
self.assertRaises(TypeError, tuple, 42)
f = open(TESTFN, "w")
try:
for i in range(5):
f.write("%d\n" % i)
finally:
f.close()
f = open(TESTFN, "r")
try:
self.assertEqual(tuple(f), ("0\n", "1\n", "2\n", "3\n", "4\n"))
f.seek(0, 0)
self.assertEqual(tuple(f),
("0\n", "1\n", "2\n", "3\n", "4\n"))
finally:
f.close()
try:
unlink(TESTFN)
except OSError:
pass
# Test filter()'s use of iterators.
def test_builtin_filter(self):
self.assertEqual(list(filter(None, SequenceClass(5))),
list(range(1, 5)))
self.assertEqual(list(filter(None, SequenceClass(0))), [])
self.assertEqual(list(filter(None, ())), [])
self.assertEqual(list(filter(None, "abc")), ["a", "b", "c"])
d = {"one": 1, "two": 2, "three": 3}
self.assertEqual(list(filter(None, d)), list(d.keys()))
self.assertRaises(TypeError, filter, None, list)
self.assertRaises(TypeError, filter, None, 42)
class Boolean:
def __init__(self, truth):
self.truth = truth
def __bool__(self):
return self.truth
bTrue = Boolean(True)
bFalse = Boolean(False)
class Seq:
def __init__(self, *args):
self.vals = args
def __iter__(self):
class SeqIter:
def __init__(self, vals):
self.vals = vals
self.i = 0
def __iter__(self):
return self
def __next__(self):
i = self.i
self.i = i + 1
if i < len(self.vals):
return self.vals[i]
else:
raise StopIteration
return SeqIter(self.vals)
seq = Seq(*([bTrue, bFalse] * 25))
self.assertEqual(list(filter(lambda x: not x, seq)), [bFalse]*25)
self.assertEqual(list(filter(lambda x: not x, iter(seq))), [bFalse]*25)
# Test max() and min()'s use of iterators.
def test_builtin_max_min(self):
self.assertEqual(max(SequenceClass(5)), 4)
self.assertEqual(min(SequenceClass(5)), 0)
self.assertEqual(max(8, -1), 8)
self.assertEqual(min(8, -1), -1)
d = {"one": 1, "two": 2, "three": 3}
self.assertEqual(max(d), "two")
self.assertEqual(min(d), "one")
self.assertEqual(max(d.values()), 3)
self.assertEqual(min(iter(d.values())), 1)
f = open(TESTFN, "w")
try:
f.write("medium line\n")
f.write("xtra large line\n")
f.write("itty-bitty line\n")
finally:
f.close()
f = open(TESTFN, "r")
try:
self.assertEqual(min(f), "itty-bitty line\n")
f.seek(0, 0)
self.assertEqual(max(f), "xtra large line\n")
finally:
f.close()
try:
unlink(TESTFN)
except OSError:
pass
# Test map()'s use of iterators.
def test_builtin_map(self):
self.assertEqual(list(map(lambda x: x+1, SequenceClass(5))),
list(range(1, 6)))
d = {"one": 1, "two": 2, "three": 3}
self.assertEqual(list(map(lambda k, d=d: (k, d[k]), d)),
list(d.items()))
dkeys = list(d.keys())
expected = [(i < len(d) and dkeys[i] or None,
i,
i < len(d) and dkeys[i] or None)
for i in range(3)]
f = open(TESTFN, "w")
try:
for i in range(10):
f.write("xy" * i + "\n") # line i has len 2*i+1
finally:
f.close()
f = open(TESTFN, "r")
try:
self.assertEqual(list(map(len, f)), list(range(1, 21, 2)))
finally:
f.close()
try:
unlink(TESTFN)
except OSError:
pass
# Test zip()'s use of iterators.
def test_builtin_zip(self):
self.assertEqual(list(zip()), [])
self.assertEqual(list(zip(*[])), [])
self.assertEqual(list(zip(*[(1, 2), 'ab'])), [(1, 'a'), (2, 'b')])
self.assertRaises(TypeError, zip, None)
self.assertRaises(TypeError, zip, range(10), 42)
self.assertRaises(TypeError, zip, range(10), zip)
self.assertEqual(list(zip(IteratingSequenceClass(3))),
[(0,), (1,), (2,)])
self.assertEqual(list(zip(SequenceClass(3))),
[(0,), (1,), (2,)])
d = {"one": 1, "two": 2, "three": 3}
self.assertEqual(list(d.items()), list(zip(d, d.values())))
# Generate all ints starting at constructor arg.
class IntsFrom:
def __init__(self, start):
self.i = start
def __iter__(self):
return self
def __next__(self):
i = self.i
self.i = i+1
return i
f = open(TESTFN, "w")
try:
f.write("a\n" "bbb\n" "cc\n")
finally:
f.close()
f = open(TESTFN, "r")
try:
self.assertEqual(list(zip(IntsFrom(0), f, IntsFrom(-100))),
[(0, "a\n", -100),
(1, "bbb\n", -99),
(2, "cc\n", -98)])
finally:
f.close()
try:
unlink(TESTFN)
except OSError:
pass
self.assertEqual(list(zip(range(5))), [(i,) for i in range(5)])
# Classes that lie about their lengths.
class NoGuessLen5:
def __getitem__(self, i):
if i >= 5:
raise IndexError
return i
class Guess3Len5(NoGuessLen5):
def __len__(self):
return 3
class Guess30Len5(NoGuessLen5):
def __len__(self):
return 30
def lzip(*args):
return list(zip(*args))
self.assertEqual(len(Guess3Len5()), 3)
self.assertEqual(len(Guess30Len5()), 30)
self.assertEqual(lzip(NoGuessLen5()), lzip(range(5)))
self.assertEqual(lzip(Guess3Len5()), lzip(range(5)))
self.assertEqual(lzip(Guess30Len5()), lzip(range(5)))
expected = [(i, i) for i in range(5)]
for x in NoGuessLen5(), Guess3Len5(), Guess30Len5():
for y in NoGuessLen5(), Guess3Len5(), Guess30Len5():
self.assertEqual(lzip(x, y), expected)
def test_unicode_join_endcase(self):
# This class inserts a Unicode object into its argument's natural
# iteration, in the 3rd position.
class OhPhooey:
def __init__(self, seq):
self.it = iter(seq)
self.i = 0
def __iter__(self):
return self
def __next__(self):
i = self.i
self.i = i+1
if i == 2:
return "fooled you!"
return next(self.it)
f = open(TESTFN, "w")
try:
f.write("a\n" + "b\n" + "c\n")
finally:
f.close()
f = open(TESTFN, "r")
# Nasty: string.join(s) can't know whether unicode.join() is needed
# until it's seen all of s's elements. But in this case, f's
# iterator cannot be restarted. So what we're testing here is
# whether string.join() can manage to remember everything it's seen
# and pass that on to unicode.join().
try:
got = " - ".join(OhPhooey(f))
self.assertEqual(got, "a\n - b\n - fooled you! - c\n")
finally:
f.close()
try:
unlink(TESTFN)
except OSError:
pass
# Test iterators with 'x in y' and 'x not in y'.
def test_in_and_not_in(self):
for sc5 in IteratingSequenceClass(5), SequenceClass(5):
for i in range(5):
self.assertIn(i, sc5)
for i in "abc", -1, 5, 42.42, (3, 4), [], {1: 1}, 3-12j, sc5:
self.assertNotIn(i, sc5)
self.assertRaises(TypeError, lambda: 3 in 12)
self.assertRaises(TypeError, lambda: 3 not in map)
d = {"one": 1, "two": 2, "three": 3, 1j: 2j}
for k in d:
self.assertIn(k, d)
self.assertNotIn(k, d.values())
for v in d.values():
self.assertIn(v, d.values())
self.assertNotIn(v, d)
for k, v in d.items():
self.assertIn((k, v), d.items())
self.assertNotIn((v, k), d.items())
f = open(TESTFN, "w")
try:
f.write("a\n" "b\n" "c\n")
finally:
f.close()
f = open(TESTFN, "r")
try:
for chunk in "abc":
f.seek(0, 0)
self.assertNotIn(chunk, f)
f.seek(0, 0)
self.assertIn((chunk + "\n"), f)
finally:
f.close()
try:
unlink(TESTFN)
except OSError:
pass
# Test iterators with operator.countOf (PySequence_Count).
def test_countOf(self):
from operator import countOf
self.assertEqual(countOf([1,2,2,3,2,5], 2), 3)
self.assertEqual(countOf((1,2,2,3,2,5), 2), 3)
self.assertEqual(countOf("122325", "2"), 3)
self.assertEqual(countOf("122325", "6"), 0)
self.assertRaises(TypeError, countOf, 42, 1)
self.assertRaises(TypeError, countOf, countOf, countOf)
d = {"one": 3, "two": 3, "three": 3, 1j: 2j}
for k in d:
self.assertEqual(countOf(d, k), 1)
self.assertEqual(countOf(d.values(), 3), 3)
self.assertEqual(countOf(d.values(), 2j), 1)
self.assertEqual(countOf(d.values(), 1j), 0)
f = open(TESTFN, "w")
try:
f.write("a\n" "b\n" "c\n" "b\n")
finally:
f.close()
f = open(TESTFN, "r")
try:
for letter, count in ("a", 1), ("b", 2), ("c", 1), ("d", 0):
f.seek(0, 0)
self.assertEqual(countOf(f, letter + "\n"), count)
finally:
f.close()
try:
unlink(TESTFN)
except OSError:
pass
# Test iterators with operator.indexOf (PySequence_Index).
def test_indexOf(self):
from operator import indexOf
self.assertEqual(indexOf([1,2,2,3,2,5], 1), 0)
self.assertEqual(indexOf((1,2,2,3,2,5), 2), 1)
self.assertEqual(indexOf((1,2,2,3,2,5), 3), 3)
self.assertEqual(indexOf((1,2,2,3,2,5), 5), 5)
self.assertRaises(ValueError, indexOf, (1,2,2,3,2,5), 0)
self.assertRaises(ValueError, indexOf, (1,2,2,3,2,5), 6)
self.assertEqual(indexOf("122325", "2"), 1)
self.assertEqual(indexOf("122325", "5"), 5)
self.assertRaises(ValueError, indexOf, "122325", "6")
self.assertRaises(TypeError, indexOf, 42, 1)
self.assertRaises(TypeError, indexOf, indexOf, indexOf)
f = open(TESTFN, "w")
try:
f.write("a\n" "b\n" "c\n" "d\n" "e\n")
finally:
f.close()
f = open(TESTFN, "r")
try:
fiter = iter(f)
self.assertEqual(indexOf(fiter, "b\n"), 1)
self.assertEqual(indexOf(fiter, "d\n"), 1)
self.assertEqual(indexOf(fiter, "e\n"), 0)
self.assertRaises(ValueError, indexOf, fiter, "a\n")
finally:
f.close()
try:
unlink(TESTFN)
except OSError:
pass
iclass = IteratingSequenceClass(3)
for i in range(3):
self.assertEqual(indexOf(iclass, i), i)
self.assertRaises(ValueError, indexOf, iclass, -1)
# Test iterators with file.writelines().
def test_writelines(self):
f = open(TESTFN, "w")
try:
self.assertRaises(TypeError, f.writelines, None)
self.assertRaises(TypeError, f.writelines, 42)
f.writelines(["1\n", "2\n"])
f.writelines(("3\n", "4\n"))
f.writelines({'5\n': None})
f.writelines({})
# Try a big chunk too.
class Iterator:
def __init__(self, start, finish):
self.start = start
self.finish = finish
self.i = self.start
def __next__(self):
if self.i >= self.finish:
raise StopIteration
result = str(self.i) + '\n'
self.i += 1
return result
def __iter__(self):
return self
class Whatever:
def __init__(self, start, finish):
self.start = start
self.finish = finish
def __iter__(self):
return Iterator(self.start, self.finish)
f.writelines(Whatever(6, 6+2000))
f.close()
f = open(TESTFN)
expected = [str(i) + "\n" for i in range(1, 2006)]
self.assertEqual(list(f), expected)
finally:
f.close()
try:
unlink(TESTFN)
except OSError:
pass
# Test iterators on RHS of unpacking assignments.
def test_unpack_iter(self):
a, b = 1, 2
self.assertEqual((a, b), (1, 2))
a, b, c = IteratingSequenceClass(3)
self.assertEqual((a, b, c), (0, 1, 2))
try: # too many values
a, b = IteratingSequenceClass(3)
except ValueError:
pass
else:
self.fail("should have raised ValueError")
try: # not enough values
a, b, c = IteratingSequenceClass(2)
except ValueError:
pass
else:
self.fail("should have raised ValueError")
try: # not iterable
a, b, c = len
except TypeError:
pass
else:
self.fail("should have raised TypeError")
a, b, c = {1: 42, 2: 42, 3: 42}.values()
self.assertEqual((a, b, c), (42, 42, 42))
f = open(TESTFN, "w")
lines = ("a\n", "bb\n", "ccc\n")
try:
for line in lines:
f.write(line)
finally:
f.close()
f = open(TESTFN, "r")
try:
a, b, c = f
self.assertEqual((a, b, c), lines)
finally:
f.close()
try:
unlink(TESTFN)
except OSError:
pass
(a, b), (c,) = IteratingSequenceClass(2), {42: 24}
self.assertEqual((a, b, c), (0, 1, 42))
@cpython_only
def test_ref_counting_behavior(self):
class C(object):
count = 0
def __new__(cls):
cls.count += 1
return object.__new__(cls)
def __del__(self):
cls = self.__class__
assert cls.count > 0
cls.count -= 1
x = C()
self.assertEqual(C.count, 1)
del x
self.assertEqual(C.count, 0)
l = [C(), C(), C()]
self.assertEqual(C.count, 3)
try:
a, b = iter(l)
except ValueError:
pass
del l
self.assertEqual(C.count, 0)
# Make sure StopIteration is a "sink state".
# This tests various things that weren't sink states in Python 2.2.1,
# plus various things that always were fine.
def test_sinkstate_list(self):
# This used to fail
a = list(range(5))
b = iter(a)
self.assertEqual(list(b), list(range(5)))
a.extend(range(5, 10))
self.assertEqual(list(b), [])
def test_sinkstate_tuple(self):
a = (0, 1, 2, 3, 4)
b = iter(a)
self.assertEqual(list(b), list(range(5)))
self.assertEqual(list(b), [])
def test_sinkstate_string(self):
a = "abcde"
b = iter(a)
self.assertEqual(list(b), ['a', 'b', 'c', 'd', 'e'])
self.assertEqual(list(b), [])
def test_sinkstate_sequence(self):
# This used to fail
a = SequenceClass(5)
b = iter(a)
self.assertEqual(list(b), list(range(5)))
a.n = 10
self.assertEqual(list(b), [])
def test_sinkstate_callable(self):
# This used to fail
def spam(state=[0]):
i = state[0]
state[0] = i+1
if i == 10:
raise AssertionError("shouldn't have gotten this far")
return i
b = iter(spam, 5)
self.assertEqual(list(b), list(range(5)))
self.assertEqual(list(b), [])
def test_sinkstate_dict(self):
# XXX For a more thorough test, see towards the end of:
# http://mail.python.org/pipermail/python-dev/2002-July/026512.html
a = {1:1, 2:2, 0:0, 4:4, 3:3}
for b in iter(a), a.keys(), a.items(), a.values():
b = iter(a)
self.assertEqual(len(list(b)), 5)
self.assertEqual(list(b), [])
def test_sinkstate_yield(self):
def gen():
for i in range(5):
yield i
b = gen()
self.assertEqual(list(b), list(range(5)))
self.assertEqual(list(b), [])
def test_sinkstate_range(self):
a = range(5)
b = iter(a)
self.assertEqual(list(b), list(range(5)))
self.assertEqual(list(b), [])
def test_sinkstate_enumerate(self):
a = range(5)
e = enumerate(a)
b = iter(e)
self.assertEqual(list(b), list(zip(range(5), range(5))))
self.assertEqual(list(b), [])
def test_3720(self):
# Avoid a crash, when an iterator deletes its next() method.
class BadIterator(object):
def __iter__(self):
return self
def __next__(self):
del BadIterator.__next__
return 1
try:
for i in BadIterator() :
pass
except TypeError:
pass
def test_extending_list_with_iterator_does_not_segfault(self):
# The code to extend a list with an iterator has a fair
# amount of nontrivial logic in terms of guessing how
# much memory to allocate in advance, "stealing" refs,
# and then shrinking at the end. This is a basic smoke
# test for that scenario.
def gen():
for i in range(500):
yield i
lst = [0] * 500
for i in range(240):
lst.pop(0)
lst.extend(gen())
self.assertEqual(len(lst), 760)
@cpython_only
def test_iter_overflow(self):
# Test for the issue 22939
it = iter(UnlimitedSequenceClass())
# Manually set `it_index` to PY_SSIZE_T_MAX-2 without a loop
it.__setstate__(sys.maxsize - 2)
self.assertEqual(next(it), sys.maxsize - 2)
self.assertEqual(next(it), sys.maxsize - 1)
with self.assertRaises(OverflowError):
next(it)
# Check that Overflow error is always raised
with self.assertRaises(OverflowError):
next(it)
def test_iter_neg_setstate(self):
it = iter(UnlimitedSequenceClass())
it.__setstate__(-42)
self.assertEqual(next(it), 0)
self.assertEqual(next(it), 1)
def test_free_after_iterating(self):
check_free_after_iterating(self, iter, SequenceClass, (0,))
def test_error_iter(self):
for typ in (DefaultIterClass, NoIterClass):
self.assertRaises(TypeError, iter, typ())
def test_main():
run_unittest(TestCase)
if __name__ == "__main__":
test_main()
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