def composite(f):
"""Defines a strategy that is built out of potentially arbitrarily many
other strategies.
This is intended to be used as a decorator. See the full
documentation for more details about how to use this function.
"""
from hypothesis.internal.reflection import copy_argspec
argspec = getargspec(f)
if (
argspec.defaults is not None and
len(argspec.defaults) == len(argspec.args)
):
raise InvalidArgument(
'A default value for initial argument will never be used')
if len(argspec.args) == 0 and not argspec.varargs:
raise InvalidArgument(
'Functions wrapped with composite must take at least one '
'positional argument.'
)
new_argspec = ArgSpec(
args=argspec.args[1:], varargs=argspec.varargs,
keywords=argspec.keywords, defaults=argspec.defaults
)
@defines_strategy
@copy_argspec(f.__name__, new_argspec)
def accept(*args, **kwargs):
class CompositeStrategy(SearchStrategy):
def do_draw(self, data):
return f(data.draw, *args, **kwargs)
return CompositeStrategy()
return accept
def test_define_function_signature_validates_function_name():
with raises(ValueError):
define_function_signature('hello world', None, ArgSpec(
args=['a', 'b'], varargs=None, keywords=None, defaults=None))
def test_copy_argspec_validates_function_name():
with raises(ValueError):
copy_argspec('hello world', ArgSpec(
args=['a', 'b'], varargs=None, keywords=None, defaults=None))
def test_copy_argspec_validates_arguments():
with raises(ValueError):
copy_argspec('hello_world', ArgSpec(
args=['a b'], varargs=None, keywords=None, defaults=None))
