Fails on typing.Type and ForwardRef #2565
Description
When we use Type[MyType] - everything is good. But, Type['MyType'] fails.
Code:
>>> from hypothesis import strategies as st
>>> from typing import Type
>>> st.from_type(Type[int])
just(<class 'int'>)
>>> st.from_type(Type['int'])
from_type(typing.Type[ForwardRef('int')])
>>> st.from_type(Type['int']).example()Output:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "hypothesis/strategies/_internal/strategies.py", line 314, in example
example_generating_inner_function()
File "hypothesis/strategies/_internal/strategies.py", line 302, in example_generating_inner_function
@settings(
File "hypothesis/core.py", line 1001, in wrapped_test
processed_args = process_arguments_to_given(
File "hypothesis/core.py", line 420, in process_arguments_to_given
search_strategy.validate()
File "hypothesis/strategies/_internal/strategies.py", line 377, in validate
self.do_validate()
File "hypothesis/strategies/_internal/collections.py", line 39, in do_validate
s.validate()
File "hypothesis/strategies/_internal/strategies.py", line 377, in validate
self.do_validate()
File "hypothesis/strategies/_internal/strategies.py", line 638, in do_validate
self.mapped_strategy.validate()
File "hypothesis/strategies/_internal/strategies.py", line 377, in validate
self.do_validate()
File "hypothesis/strategies/_internal/lazy.py", line 118, in do_validate
w.validate()
File "hypothesis/strategies/_internal/strategies.py", line 377, in validate
self.do_validate()
File "hypothesis/strategies/_internal/strategies.py", line 638, in do_validate
self.mapped_strategy.validate()
File "hypothesis/strategies/_internal/strategies.py", line 377, in validate
self.do_validate()
File "hypothesis/strategies/_internal/collections.py", line 39, in do_validate
s.validate()
File "hypothesis/strategies/_internal/strategies.py", line 377, in validate
self.do_validate()
File "hypothesis/strategies/_internal/lazy.py", line 118, in do_validate
w.validate()
File "hypothesis/strategies/_internal/strategies.py", line 378, in validate
self.is_empty
File "hypothesis/strategies/_internal/strategies.py", line 125, in accept
recur(self)
File "hypothesis/strategies/_internal/strategies.py", line 121, in recur
mapping[strat] = getattr(strat, calculation)(recur)
File "hypothesis/strategies/_internal/deferred.py", line 80, in calc_is_empty
return recur(self.wrapped_strategy)
File "hypothesis/strategies/_internal/deferred.py", line 43, in wrapped_strategy
result = self.__definition()
File "hypothesis/strategies/_internal/core.py", line 1389, in <lambda>
lambda thing: deferred(lambda: _from_type(thing)),
File "hypothesis/strategies/_internal/core.py", line 1477, in _from_type
return types.from_typing_type(thing)
File "hypothesis/strategies/_internal/types.py", line 282, in from_typing_type
strategies = [
File "hypothesis/strategies/_internal/types.py", line 283, in <listcomp>
v if isinstance(v, st.SearchStrategy) else v(thing)
File "hypothesis/strategies/_internal/types.py", line 507, in resolve_Type
raise ResolutionFailed(
hypothesis.errors.ResolutionFailed:
thing=typing.Type[ForwardRef('int')] cannot be resolved.
Upgrading to python>=3.6 may fix this problem via improvements to the typing module.