def test_function_type_with_invalidation():
foo_instances = []
@lazy
class foo():
def __init__(self):
self.i = 0
foo_instances.append(self)
def watch(self, callback):
self.callback = callback
def __call__(self):
self.i += 1
return self.i
with lazy_invalidation():
assert len(foo_instances) == 1
assert foo_instances[0].i == 0
assert not hasattr(foo_instances[0], 'callback')
assert foo() == 1
assert foo_instances[0].i == 1
assert hasattr(foo_instances[0], 'callback')
assert foo() == 1
foo_instances[0].callback()
assert foo_instances[0].i == 1
assert foo() == 2
assert foo_instances[0].i == 2
assert foo() == 2
assert foo_instances[0].i == 2
assert len(foo_instances) == 1
def test_dependency_still_watched_when_no_explicit_references_remain():
listener = DummyListener()
@lazy(listener = listener)
def foo():
return 5
@lazy
def bar():
return foo()
with lazy_invalidation():
foo_ref = weakref.ref(foo)
assert listener.retain_calls == 0
assert listener.release_calls == 0
assert bar() == 5
foo = lambda : 6
assert listener.retain_calls == 1
assert listener.release_calls == 0
assert bar() == 5
listener.callback()
assert listener.retain_calls == 1
assert listener.release_calls == 1
assert bar() == 6
def test_lazy_values_can_be_garbage_collected_with_invalidation():
@lazy
def foo():
return 5
with lazy_invalidation():
foo_ref = weakref.ref(foo)
assert foo() == 5
foo = None
assert foo_ref() is None
def test_unwatch_called_after_garbage_collection():
listener = DummyListener()
@lazy(listener = listener)
def foo():
return 5
with lazy_invalidation():
foo_ref = weakref.ref(foo)
assert listener.retain_calls == 0
assert listener.release_calls == 0
assert foo() == 5
assert listener.retain_calls == 1
assert listener.release_calls == 0
assert foo_ref() is not None
foo = None
assert listener.retain_calls == 1
assert listener.release_calls == 1
assert foo_ref() is None
listener.callback()
def test_watchable_property():
values = count()
watched = {}
class Bar(property):
def __init__(self):
property.__init__(self, fget = self.getter)
def getter(self, obj):
if obj is None:
return self
return values.next()
def watch(self, obj, storage, callback):
watched[obj] = callback
storage.obj = obj
def unwatch(self, storage):
del watched[storage.obj]
class Foo(object):
BAR = lazy(Bar())
with lazy_invalidation():
assert hasattr(Foo.BAR, '__get__')
foo = Foo()
assert not watched
assert foo.BAR == 0
assert watched
callback = watched.itervalues().next()
assert foo.BAR == 0
callback()
assert foo.BAR == 1
assert foo.BAR == 1
callback()
assert foo.BAR == 2
assert foo.BAR == 2
assert watched
assert not watched
