def __len__(self):
assert self._length in {None, 'parent'} or isinstance(
self._length, int)
if self._length is None and \
not is_method_redefined('__iter__', Transform, self) \
or self._length == 'parent':
self._length = len(self._extractor)
return super().__len__()
def categories(self) -> CategoriesInfo:
if self.is_cache_initialized():
return self._categories
elif self._categories is not None:
return self._categories
elif any(
is_method_redefined('categories', Transform, t[0])
for t in self._transforms):
self.init_cache()
return self._categories
else:
return self._source.categories()
def transform(self, method: Type[Transform], *args, **kwargs):
# Flush accumulated changes
if not self._storage.is_empty():
source = self._merged()
self._storage = DatasetItemStorage()
else:
source = self._source
if not self._transforms:
# The stack of transforms only needs a single source
self._source = source
self._transforms.append((method, args, kwargs))
if is_method_redefined('categories', Transform, method):
self._categories = None
self._length = None
def test_can_detect_changes_in_patched_instance(self):
obj = self.Base()
with mock.patch.object(obj, 'method'):
self.assertTrue(is_method_redefined('method', self.Base, obj))
def test_can_detect_changes_in_derived_instance(self):
class Derived(self.Base):
def method(self):
pass
self.assertTrue(is_method_redefined('method', self.Base, Derived()))
def test_can_detect_no_changes_in_derived_class(self):
class Derived(self.Base):
pass
self.assertFalse(is_method_redefined('method', self.Base, Derived))
