def test_dict_items_method_optional(self):
# Test the instance method calls the top-level function correctly.
expr = expression.dict_items().dict_items(optional=True)
expected = [
create_graph(
DictItemObserver(notify=True, optional=False),
DictItemObserver(notify=True, optional=True),
),
]
actual = expr._as_graphs()
self.assertEqual(actual, expected)
def test_dict_items_optional_true(self):
expr = expression.dict_items(optional=True)
expected = [
create_graph(DictItemObserver(notify=True, optional=True), ),
]
actual = expr._as_graphs()
self.assertEqual(actual, expected)
def dict_items(notify=True, optional=False):
""" Create a new expression for observing items inside a dict.
Events emitted (if any) will be instances of
:class:`~traits.observation.events.DictChangeEvent`.
If an expression with ``dict_items`` is further extended, the
**values** of the dict will be given to the next item in the expression.
For example, the following observes a trait named "number" on any object
that is one of the values in the dict named "mapping"::
trait("mapping").dict_items().trait("number")
Parameters
----------
notify : bool, optional
Whether to notify for changes. Default is to notify.
optional : bool, optional
Whether to ignore this if the upstream object is not a dict.
Default is false and an error will be raised if the object is not
a dict.
Returns
-------
new_expression : ObserverExpression
"""
observer = DictItemObserver(notify=notify, optional=optional)
return SingleObserverExpression(observer)
def create_observer(**kwargs):
""" Convenience function for creating DictItemObserver with default values.
"""
values = dict(
notify=True,
optional=False,
)
values.update(kwargs)
return DictItemObserver(**values)
def test_equal_observers(self):
observer1 = DictItemObserver(notify=False, optional=False)
observer2 = DictItemObserver(notify=False, optional=False)
self.assertEqual(observer1, observer2)
self.assertEqual(hash(observer1), hash(observer2))
def test_not_equal_different_type(self):
observer1 = DictItemObserver(notify=False, optional=False)
imposter = mock.Mock()
imposter.notify = False
imposter.optional = False
self.assertNotEqual(observer1, imposter)
def test_not_equal_optional(self):
observer1 = DictItemObserver(notify=True, optional=True)
observer2 = DictItemObserver(notify=True, optional=False)
self.assertNotEqual(observer1, observer2)