def test_source_setdefault_as_subsection():
config = DictSource()
with pytest.raises(AttributeError):
config.a.b = 1
config.setdefault('a', {}).b = 1
assert config.a.b == 1
def test_source_setdefault():
config = DictSource({'a': 1})
assert config.setdefault('a', 10) == 1
assert config.setdefault('nonexisting', 10) == 10
assert config.nonexisting == 10