django/tests/utils_tests/test_simplelazyobject.py

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from __future__ import unicode_literals
import copy
import pickle
import sys
from django.utils import six
from django.utils.unittest import TestCase
from django.utils.functional import SimpleLazyObject, empty
class _ComplexObject(object):
def __init__(self, name):
self.name = name
def __eq__(self, other):
return self.name == other.name
def __hash__(self):
return hash(self.name)
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if six.PY3:
def __bytes__(self):
return ("I am _ComplexObject(%r)" % self.name).encode("utf-8")
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def __str__(self):
return self.name
else:
def __str__(self):
return b"I am _ComplexObject(%r)" % str(self.name)
def __unicode__(self):
return self.name
def __repr__(self):
return "_ComplexObject(%r)" % self.name
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complex_object = lambda: _ComplexObject("joe")
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class TestUtilsSimpleLazyObject(TestCase):
"""
Tests for SimpleLazyObject
"""
# Note that concrete use cases for SimpleLazyObject are also found in the
# auth context processor tests (unless the implementation of that function
# is changed).
def test_equality(self):
self.assertEqual(complex_object(), SimpleLazyObject(complex_object))
self.assertEqual(SimpleLazyObject(complex_object), complex_object())
def test_hash(self):
# hash() equality would not be true for many objects, but it should be
# for _ComplexObject
self.assertEqual(hash(complex_object()),
hash(SimpleLazyObject(complex_object)))
def test_repr(self):
# First, for an unevaluated SimpleLazyObject
x = SimpleLazyObject(complex_object)
# __repr__ contains __repr__ of setup function and does not evaluate
# the SimpleLazyObject
self.assertEqual("<SimpleLazyObject: %r>" % complex_object, repr(x))
self.assertEqual(empty, x._wrapped)
# Second, for an evaluated SimpleLazyObject
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name = x.name # evaluate
self.assertTrue(isinstance(x._wrapped, _ComplexObject))
# __repr__ contains __repr__ of wrapped object
self.assertEqual("<SimpleLazyObject: %r>" % x._wrapped, repr(x))
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def test_bytes(self):
self.assertEqual(b"I am _ComplexObject('joe')",
bytes(SimpleLazyObject(complex_object)))
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def test_text(self):
self.assertEqual("joe", six.text_type(SimpleLazyObject(complex_object)))
def test_class(self):
# This is important for classes that use __class__ in things like
# equality tests.
self.assertEqual(_ComplexObject, SimpleLazyObject(complex_object).__class__)
def test_deepcopy(self):
# Check that we *can* do deep copy, and that it returns the right
# objects.
# First, for an unevaluated SimpleLazyObject
s = SimpleLazyObject(complex_object)
self.assertIs(s._wrapped, empty)
s2 = copy.deepcopy(s)
# something has gone wrong is s is evaluated
self.assertIs(s._wrapped, empty)
self.assertEqual(s2, complex_object())
# Second, for an evaluated SimpleLazyObject
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name = s.name # evaluate
self.assertIsNot(s._wrapped, empty)
s3 = copy.deepcopy(s)
self.assertEqual(s3, complex_object())
def test_none(self):
i = [0]
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def f():
i[0] += 1
return None
x = SimpleLazyObject(f)
self.assertEqual(str(x), "None")
self.assertEqual(i, [1])
self.assertEqual(str(x), "None")
self.assertEqual(i, [1])
def test_bool(self):
x = SimpleLazyObject(lambda: 3)
self.assertTrue(x)
x = SimpleLazyObject(lambda: 0)
self.assertFalse(x)
def test_pickle_complex(self):
# See ticket #16563
x = SimpleLazyObject(complex_object)
pickled = pickle.dumps(x)
unpickled = pickle.loads(pickled)
self.assertEqual(unpickled, x)
self.assertEqual(six.text_type(unpickled), six.text_type(x))
self.assertEqual(unpickled.name, x.name)
def test_dict(self):
# See ticket #18447
lazydict = SimpleLazyObject(lambda: {'one': 1})
self.assertEqual(lazydict['one'], 1)
lazydict['one'] = -1
self.assertEqual(lazydict['one'], -1)
del lazydict['one']
with self.assertRaises(KeyError):
lazydict['one']
def test_trace(self):
# See ticket #19456
old_trace_func = sys.gettrace()
try:
def trace_func(frame, event, arg):
frame.f_locals['self'].__class__
if old_trace_func is not None:
old_trace_func(frame, event, arg)
sys.settrace(trace_func)
SimpleLazyObject(None)
finally:
sys.settrace(old_trace_func)