def test_validator_not_notified_when_theres_no_change(owner_with_validator):
instance = owner_with_validator
value_1 = Sentinel('value_1')
value_2 = Sentinel('value_2')
instance.observable = value_1
instance.observable = value_1
instance.observable = value_2
expected = [((instance, undefined_value, value_1), ),
((instance, value_1, value_2), )]
assert instance.validator.call_args_list == expected
def test_observer_not_notified_when_theres_no_change(
owner_with_instance_observer):
instance = owner_with_instance_observer
value_1 = Sentinel("value_1")
value_2 = Sentinel("value_2")
instance.observable = value_1
instance.observable = value_1
instance.observable = value_2
expected = [((instance, undefined_value, value_1), ),
((instance, value_1, value_2), )]
assert instance.observer.call_args_list == expected
import typing as t
from pca.utils.sentinel import Sentinel
undefined_value = Sentinel(module="pca.data.descriptors",
name="undefined_value")
Owner = t.TypeVar("Owner")
Value = t.TypeVar("Value")
import typing as t
from pca.utils.collections import OrderedSet
from pca.utils.inspect import is_argspec_valid
from pca.utils.sentinel import Sentinel
# sentinel object for expressing that a value of a observable hasn't been set
# NB: None object might be a valid value
undefined_value = Sentinel(module='pca.data.observable',
name='undefined_value')
Owner = t.TypeVar('Owner')
Value = t.TypeVar('Value')
Preprocessor = t.Callable[[Value], Value]
Validator = t.Callable[[Value], None] # raises errors
Observer = t.Callable[[Owner, Value, Value], None]
class Observable:
_owner: Owner
_label: str
# pattern for __dict__ key on the owner class; space char is intended to be
# sure we are not colliding with any proper attribute name
_observer_key_pattern = '%s instance observers'
def __init__(self,
default=undefined_value,
preprocessor: Preprocessor = None,
validator: Validator = None,
class_observers: t.Iterable[Observer] = None):
def value():
return Sentinel(name='value')
import typing as t
from pca.utils.sentinel import Sentinel
undefined_value = Sentinel(module='pca.data.descriptors',
name='undefined_value')
Owner = t.TypeVar('Owner')
Value = t.TypeVar('Value')
import typing as t
from pca.utils.collections import OrderedSet
from pca.utils.inspect import is_argspec_valid
from pca.utils.sentinel import Sentinel
# sentinel object for expressing that a value of a observable hasn't been set
# NB: None object might be a valid value
undefined_value = Sentinel(module="pca.data.observable",
name="undefined_value")
Owner = t.TypeVar("Owner")
Value = t.TypeVar("Value")
Preprocessor = t.Callable[[Value], Value]
Validator = t.Callable[[Value], None] # raises errors
Observer = t.Callable[[Owner, Value, Value], None]
class Observable:
_owner: Owner
_label: str
# pattern for __dict__ key on the owner class; space char is intended to be
# sure we are not colliding with any proper attribute name
_observer_key_pattern = "%s instance observers"
def __init__(
self,
default=undefined_value,
preprocessor: Preprocessor = None,
validator: Validator = None,
def value():
return Sentinel(name="value")