1
0
mirror of https://github.com/django/django.git synced 2025-01-03 15:06:09 +00:00
django/tests/utils_tests/test_functional.py
Ran Benita ae94077e7d Made proxy class in lazy() prepare eagerly.
Previously, the proxy class was prepared lazily:

  lazy_identity = lazy(identity, int)
  lazy_identity(10)  # prepared here
  lazy_identity(10)

This has a slight advantage that if the lazy doesn't end up getting
used, the preparation work is skipped, however that's not very likely.

Besides this laziness, it is also inconsistent in that the methods which
are wrapped directly (__str__ etc.) are prepared already when __proxy__
is defined, and there is a weird half-initialized state.

This change it so that everything is prepared already on the first line
of the example above.
2023-06-12 05:45:44 +02:00

326 lines
10 KiB
Python

from django.test import SimpleTestCase
from django.utils.functional import cached_property, classproperty, lazy
from django.utils.version import PY312
class FunctionalTests(SimpleTestCase):
def test_lazy(self):
t = lazy(lambda: tuple(range(3)), list, tuple)
for a, b in zip(t(), range(3)):
self.assertEqual(a, b)
def test_lazy_base_class(self):
"""lazy also finds base class methods in the proxy object"""
class Base:
def base_method(self):
pass
class Klazz(Base):
pass
t = lazy(lambda: Klazz(), Klazz)()
self.assertIn("base_method", dir(t))
def test_lazy_base_class_override(self):
"""lazy finds the correct (overridden) method implementation"""
class Base:
def method(self):
return "Base"
class Klazz(Base):
def method(self):
return "Klazz"
t = lazy(lambda: Klazz(), Base)()
self.assertEqual(t.method(), "Klazz")
def test_lazy_object_to_string(self):
class Klazz:
def __str__(self):
return "Î am ā Ǩlâzz."
def __bytes__(self):
return b"\xc3\x8e am \xc4\x81 binary \xc7\xa8l\xc3\xa2zz."
t = lazy(lambda: Klazz(), Klazz)()
self.assertEqual(str(t), "Î am ā Ǩlâzz.")
self.assertEqual(bytes(t), b"\xc3\x8e am \xc4\x81 binary \xc7\xa8l\xc3\xa2zz.")
def assertCachedPropertyWorks(self, attr, Class):
with self.subTest(attr=attr):
def get(source):
return getattr(source, attr)
obj = Class()
class SubClass(Class):
pass
subobj = SubClass()
# Docstring is preserved.
self.assertEqual(get(Class).__doc__, "Here is the docstring...")
self.assertEqual(get(SubClass).__doc__, "Here is the docstring...")
# It's cached.
self.assertEqual(get(obj), get(obj))
self.assertEqual(get(subobj), get(subobj))
# The correct value is returned.
self.assertEqual(get(obj)[0], 1)
self.assertEqual(get(subobj)[0], 1)
# State isn't shared between instances.
obj2 = Class()
subobj2 = SubClass()
self.assertNotEqual(get(obj), get(obj2))
self.assertNotEqual(get(subobj), get(subobj2))
# It behaves like a property when there's no instance.
self.assertIsInstance(get(Class), cached_property)
self.assertIsInstance(get(SubClass), cached_property)
# 'other_value' doesn't become a property.
self.assertTrue(callable(obj.other_value))
self.assertTrue(callable(subobj.other_value))
def test_cached_property(self):
"""cached_property caches its value and behaves like a property."""
class Class:
@cached_property
def value(self):
"""Here is the docstring..."""
return 1, object()
@cached_property
def __foo__(self):
"""Here is the docstring..."""
return 1, object()
def other_value(self):
"""Here is the docstring..."""
return 1, object()
other = cached_property(other_value)
attrs = ["value", "other", "__foo__"]
for attr in attrs:
self.assertCachedPropertyWorks(attr, Class)
def test_cached_property_auto_name(self):
"""
cached_property caches its value and behaves like a property
on mangled methods or when the name kwarg isn't set.
"""
class Class:
@cached_property
def __value(self):
"""Here is the docstring..."""
return 1, object()
def other_value(self):
"""Here is the docstring..."""
return 1, object()
other = cached_property(other_value)
attrs = ["_Class__value", "other"]
for attr in attrs:
self.assertCachedPropertyWorks(attr, Class)
def test_cached_property_reuse_different_names(self):
"""Disallow this case because the decorated function wouldn't be cached."""
type_msg = (
"Cannot assign the same cached_property to two different names ('a' and "
"'b')."
)
if PY312:
error_type = TypeError
msg = type_msg
else:
error_type = RuntimeError
msg = "Error calling __set_name__"
with self.assertRaisesMessage(error_type, msg) as ctx:
class ReusedCachedProperty:
@cached_property
def a(self):
pass
b = a
if not PY312:
self.assertEqual(str(ctx.exception.__context__), str(TypeError(type_msg)))
def test_cached_property_reuse_same_name(self):
"""
Reusing a cached_property on different classes under the same name is
allowed.
"""
counter = 0
@cached_property
def _cp(_self):
nonlocal counter
counter += 1
return counter
class A:
cp = _cp
class B:
cp = _cp
a = A()
b = B()
self.assertEqual(a.cp, 1)
self.assertEqual(b.cp, 2)
self.assertEqual(a.cp, 1)
def test_cached_property_set_name_not_called(self):
cp = cached_property(lambda s: None)
class Foo:
pass
Foo.cp = cp
msg = (
"Cannot use cached_property instance without calling __set_name__() on it."
)
with self.assertRaisesMessage(TypeError, msg):
Foo().cp
def test_lazy_add_int(self):
lazy_4 = lazy(lambda: 4, int)
lazy_5 = lazy(lambda: 5, int)
self.assertEqual(4 + lazy_5(), 9)
self.assertEqual(lazy_4() + 5, 9)
self.assertEqual(lazy_4() + lazy_5(), 9)
def test_lazy_add_list(self):
lazy_4 = lazy(lambda: [4], list)
lazy_5 = lazy(lambda: [5], list)
self.assertEqual([4] + lazy_5(), [4, 5])
self.assertEqual(lazy_4() + [5], [4, 5])
self.assertEqual(lazy_4() + lazy_5(), [4, 5])
def test_lazy_add_str(self):
lazy_a = lazy(lambda: "a", str)
lazy_b = lazy(lambda: "b", str)
self.assertEqual("a" + lazy_b(), "ab")
self.assertEqual(lazy_a() + "b", "ab")
self.assertEqual(lazy_a() + lazy_b(), "ab")
def test_lazy_mod_int(self):
lazy_4 = lazy(lambda: 4, int)
lazy_5 = lazy(lambda: 5, int)
self.assertEqual(4 % lazy_5(), 4)
self.assertEqual(lazy_4() % 5, 4)
self.assertEqual(lazy_4() % lazy_5(), 4)
def test_lazy_mod_str(self):
lazy_a = lazy(lambda: "a%s", str)
lazy_b = lazy(lambda: "b", str)
self.assertEqual("a%s" % lazy_b(), "ab")
self.assertEqual(lazy_a() % "b", "ab")
self.assertEqual(lazy_a() % lazy_b(), "ab")
def test_lazy_mul_int(self):
lazy_4 = lazy(lambda: 4, int)
lazy_5 = lazy(lambda: 5, int)
self.assertEqual(4 * lazy_5(), 20)
self.assertEqual(lazy_4() * 5, 20)
def test_lazy_mul_list(self):
lazy_4 = lazy(lambda: [4], list)
lazy_5 = lazy(lambda: 5, int)
self.assertEqual([4] * lazy_5(), [4, 4, 4, 4, 4])
self.assertEqual(lazy_4() * 5, [4, 4, 4, 4, 4])
self.assertEqual(lazy_4() * lazy_5(), [4, 4, 4, 4, 4])
def test_lazy_mul_str(self):
lazy_a = lazy(lambda: "a", str)
lazy_5 = lazy(lambda: 5, int)
self.assertEqual("a" * lazy_5(), "aaaaa")
self.assertEqual(lazy_a() * 5, "aaaaa")
self.assertEqual(lazy_a() * lazy_5(), "aaaaa")
def test_lazy_equality(self):
"""
== and != work correctly for Promises.
"""
lazy_a = lazy(lambda: 4, int)
lazy_b = lazy(lambda: 4, int)
lazy_c = lazy(lambda: 5, int)
self.assertEqual(lazy_a(), lazy_b())
self.assertNotEqual(lazy_b(), lazy_c())
def test_lazy_repr_text(self):
original_object = "Lazy translation text"
lazy_obj = lazy(lambda: original_object, str)
self.assertEqual(repr(original_object), repr(lazy_obj()))
def test_lazy_repr_int(self):
original_object = 15
lazy_obj = lazy(lambda: original_object, int)
self.assertEqual(repr(original_object), repr(lazy_obj()))
def test_lazy_repr_bytes(self):
original_object = b"J\xc3\xbcst a str\xc3\xadng"
lazy_obj = lazy(lambda: original_object, bytes)
self.assertEqual(repr(original_object), repr(lazy_obj()))
def test_lazy_regular_method(self):
original_object = 15
lazy_obj = lazy(lambda: original_object, int)
self.assertEqual(original_object.bit_length(), lazy_obj().bit_length())
def test_lazy_bytes_and_str_result_classes(self):
lazy_obj = lazy(lambda: "test", str, bytes)
self.assertEqual(str(lazy_obj()), "test")
def test_lazy_str_cast_mixed_result_types(self):
lazy_value = lazy(lambda: [1], str, list)()
self.assertEqual(str(lazy_value), "[1]")
def test_lazy_str_cast_mixed_bytes_result_types(self):
lazy_value = lazy(lambda: [1], bytes, list)()
self.assertEqual(str(lazy_value), "[1]")
def test_classproperty_getter(self):
class Foo:
foo_attr = 123
def __init__(self):
self.foo_attr = 456
@classproperty
def foo(cls):
return cls.foo_attr
class Bar:
bar = classproperty()
@bar.getter
def bar(cls):
return 123
self.assertEqual(Foo.foo, 123)
self.assertEqual(Foo().foo, 123)
self.assertEqual(Bar.bar, 123)
self.assertEqual(Bar().bar, 123)
def test_classproperty_override_getter(self):
class Foo:
@classproperty
def foo(cls):
return 123
@foo.getter
def foo(cls):
return 456
self.assertEqual(Foo.foo, 456)
self.assertEqual(Foo().foo, 456)