Open
Description
Steps to reproduce
from unittest.mock import patch
class NewPrinter:
pass
with patch("pprint.PrettyPrinter", new_callable=lambda: NewPrinter) as patched_printer:
print(patched_printer) # <class '__main__.NewPrinter'>
reveal_type(patched_printer) # "Union[unittest.mock.MagicMock, unittest.mock.AsyncMock]"
Same deal with unittest.mock.patch.object
from unittest.mock import patch
import pprint
class NewPrinter:
...
with patch.object(pprint, "PrettyPrinter", new_callable=lambda: NewPrinter) as patched_printer:
print(patched_printer) # <class '__main__.NewPrinter'>
reveal_type(patched_printer) # "Union[unittest.mock.MagicMock, unittest.mock.AsyncMock]"
Suggested fix
We discuss unittest.mock.patch
in the following, but the same principles apply to unittest.mock.patch.object
too
Current signatures:
@overload
def __call__(
self,
target: str,
new: _T,
spec: Any | None = ...,
create: bool = ...,
spec_set: Any | None = ...,
autospec: Any | None = ...,
new_callable: Any | None = ...,
**kwargs: Any,
) -> _patch[_T]: ...
@overload
def __call__(
self,
target: str,
*,
spec: Any | None = ...,
create: bool = ...,
spec_set: Any | None = ...,
autospec: Any | None = ...,
new_callable: Any | None = ...,
**kwargs: Any,
) -> _patch_default_new: ...
There are 2 problems here:
new_callable
shouldn't beAny | None
in the first place, it should only acceptCallable| None
, as the it will raise if the provided value is not a callablewith patch("pprint.PrettyPrinter", new_callable=1) as patched_printer: # TypeError: 'int' object is not callable
- Need to differentiate the case where new_callable is provided and left as default None
- When
new_callable: Callable[..., T]
, returns_patch[_T]
- When
new_callable: None = ...
, returns_patch_default_new
- When
Seems like this would do the job:
@overload
def __call__(
self,
target: str,
new: _T,
spec: Any | None = ...,
create: bool = ...,
spec_set: Any | None = ...,
autospec: Any | None = ...,
new_callable: Callable[..., Any] | None = ...,
**kwargs: Any,
) -> _patch[_T]: ...
@overload
def __call__(
self,
target: str,
*,
spec: Any | None = ...,
create: bool = ...,
spec_set: Any | None = ...,
autospec: Any | None = ...,
new_callable: Callable[..., _T],
**kwargs: Any,
) -> _patch[_T]
@overload
def __call__(
self,
target: str,
*,
spec: Any | None = ...,
create: bool = ...,
spec_set: Any | None = ...,
autospec: Any | None = ...,
new_callable: None = ...,
**kwargs: Any,
) -> _patch_default_new: ...
Testing results
from unittest.mock import patch
class NewPrinter:
pass
with patch("pprint.PrettyPrinter") as patched_printer:
print(patched_printer) # <MagicMock name='PrettyPrinter' id='125908774402896'>
reveal_type(patched_printer) # MagicMock | AsyncMock
with patch("pprint.PrettyPrinter", new=NewPrinter) as patched_printer:
print(patched_printer) # <class '__main__.NewPrinter'>
reveal_type(patched_printer) # type[NewPrinter]
with patch("pprint.PrettyPrinter", new_callable=lambda: NewPrinter) as patched_printer:
print(patched_printer) # <class '__main__.NewPrinter'>
reveal_type(patched_printer) # type[NewPrinter]
# No overload variant matches for non-callable type
with patch("pprint.PrettyPrinter", new_callable="non-callable") as patched_printer:
...
Haven't tried unittest.mock.patch.object
yet, but probably same thing
Would be great to see what the maintainers think.
I'll dig deeper and try to open a PR, maybe this weekend, will be my first PR in typeshed :)
Metadata
Metadata
Assignees
Labels
No labels