summaryrefslogtreecommitdiffstats
path: root/Lib/test/test_iterlen.py
diff options
context:
space:
mode:
Diffstat (limited to 'Lib/test/test_iterlen.py')
-rw-r--r--Lib/test/test_iterlen.py62
1 files changed, 29 insertions, 33 deletions
diff --git a/Lib/test/test_iterlen.py b/Lib/test/test_iterlen.py
index 9101f6c..152f5fc 100644
--- a/Lib/test/test_iterlen.py
+++ b/Lib/test/test_iterlen.py
@@ -45,31 +45,21 @@ import unittest
from test import support
from itertools import repeat
from collections import deque
-from builtins import len as _len
+from operator import length_hint
n = 10
-def len(obj):
- try:
- return _len(obj)
- except TypeError:
- try:
- # note: this is an internal undocumented API,
- # don't rely on it in your own programs
- return obj.__length_hint__()
- except AttributeError:
- raise TypeError
class TestInvariantWithoutMutations:
def test_invariant(self):
it = self.it
for i in reversed(range(1, n+1)):
- self.assertEqual(len(it), i)
+ self.assertEqual(length_hint(it), i)
next(it)
- self.assertEqual(len(it), 0)
+ self.assertEqual(length_hint(it), 0)
self.assertRaises(StopIteration, next, it)
- self.assertEqual(len(it), 0)
+ self.assertEqual(length_hint(it), 0)
class TestTemporarilyImmutable(TestInvariantWithoutMutations):
@@ -78,12 +68,12 @@ class TestTemporarilyImmutable(TestInvariantWithoutMutations):
# length immutability during iteration
it = self.it
- self.assertEqual(len(it), n)
+ self.assertEqual(length_hint(it), n)
next(it)
- self.assertEqual(len(it), n-1)
+ self.assertEqual(length_hint(it), n-1)
self.mutate()
self.assertRaises(RuntimeError, next, it)
- self.assertEqual(len(it), 0)
+ self.assertEqual(length_hint(it), 0)
## ------- Concrete Type Tests -------
@@ -92,10 +82,6 @@ class TestRepeat(TestInvariantWithoutMutations, unittest.TestCase):
def setUp(self):
self.it = repeat(None, n)
- def test_no_len_for_infinite_repeat(self):
- # The repeat() object can also be infinite
- self.assertRaises(TypeError, len, repeat(None))
-
class TestXrange(TestInvariantWithoutMutations, unittest.TestCase):
def setUp(self):
@@ -167,14 +153,15 @@ class TestList(TestInvariantWithoutMutations, unittest.TestCase):
it = iter(d)
next(it)
next(it)
- self.assertEqual(len(it), n-2)
+ self.assertEqual(length_hint(it), n - 2)
d.append(n)
- self.assertEqual(len(it), n-1) # grow with append
+ self.assertEqual(length_hint(it), n - 1) # grow with append
d[1:] = []
- self.assertEqual(len(it), 0)
+ self.assertEqual(length_hint(it), 0)
self.assertEqual(list(it), [])
d.extend(range(20))
- self.assertEqual(len(it), 0)
+ self.assertEqual(length_hint(it), 0)
+
class TestListReversed(TestInvariantWithoutMutations, unittest.TestCase):
@@ -186,32 +173,41 @@ class TestListReversed(TestInvariantWithoutMutations, unittest.TestCase):
it = reversed(d)
next(it)
next(it)
- self.assertEqual(len(it), n-2)
+ self.assertEqual(length_hint(it), n - 2)
d.append(n)
- self.assertEqual(len(it), n-2) # ignore append
+ self.assertEqual(length_hint(it), n - 2) # ignore append
d[1:] = []
- self.assertEqual(len(it), 0)
+ self.assertEqual(length_hint(it), 0)
self.assertEqual(list(it), []) # confirm invariant
d.extend(range(20))
- self.assertEqual(len(it), 0)
+ self.assertEqual(length_hint(it), 0)
## -- Check to make sure exceptions are not suppressed by __length_hint__()
class BadLen(object):
- def __iter__(self): return iter(range(10))
+ def __iter__(self):
+ return iter(range(10))
+
def __len__(self):
raise RuntimeError('hello')
+
class BadLengthHint(object):
- def __iter__(self): return iter(range(10))
+ def __iter__(self):
+ return iter(range(10))
+
def __length_hint__(self):
raise RuntimeError('hello')
+
class NoneLengthHint(object):
- def __iter__(self): return iter(range(10))
+ def __iter__(self):
+ return iter(range(10))
+
def __length_hint__(self):
- return None
+ return NotImplemented
+
class TestLengthHintExceptions(unittest.TestCase):