Function test_subclass_default_value

tests/test_traitlets.py:1848–1861

Test deprecated default_value=None behavior for Container subclass traits

(Trait, default_value)

    ((List, []), (Tuple, ()), (Set, set())),  # noqa: PT007
)
def test_subclass_default_value(Trait, default_value):
    """Test deprecated default_value=None behavior for Container subclass traits"""

    class SubclassTrait(Trait):  # type:ignore
        def __init__(self, default_value=None):
            super().__init__(default_value=default_value)

    class C(HasTraits):
        t = SubclassTrait()

    # test default value
    c = C()
    assert type(c.t) is type(default_value)
    assert c.t == default_value


class CRegExpTrait(HasTraits):