def test_initialises_field():
one = Field('one')
assert one.name == 'one'
assert one.mapping('some_string') == 'some_string'
assert one.mapping('10') == '10'
assert one.mapping(10) == '10'
two = Field('two', 5)
assert two.default == 5
assert two.mapping(10) == 10
assert two.mapping('10') == 10
assert two.mapping(None) is None
three = Field('three', 'default value')
assert three.default == 'default value'
assert three.mapping('10') == '10'
assert three.mapping(10) == '10'
assert three.mapping(None) is None
four = Field('four', None, int)
assert four.default is None
assert four.mapping('10') == 10
assert four.mapping(10) == 10
assert four.mapping(None) is None
def test_none_as_default_value_means_str_as_parser_by_default():
f = Field('name', default=None)
assert f.mapping('10') == '10'
assert f.mapping([10]) == '[10]'