Type improvements

CHANGELOG.rst

@@ -10,6 +10,12 @@
 
   Note however that this is just a stop gap measure, and new code should use ``MockerFixture`` for type annotations.
 
+* Improved typing for ``MockerFixture.patch``  (`#201`_). Thanks `@srittau`_ for the PR.
+
+.. _@srittau: https://github.com/srittau
+.. _#201: https://github.com/pytest-dev/pytest-mock/pull/201
+
+
 3.3.0 (2020-08-21)
 ------------------
 

src/pytest_mock/plugin.py

@@ -1,6 +1,6 @@
 import builtins
 import unittest.mock
-from typing import cast, Generator, Mapping, Iterable, Tuple
+from typing import cast, overload, Generator, Mapping, Iterable, Tuple, TypeVar
 from typing import Any
 from typing import Callable
 from typing import Dict
@@ -17,6 +17,8 @@
 
 import pytest
 
+_T = TypeVar("_T")
+
 
 def _get_mock_module(config):
     """
@@ -50,7 +52,9 @@ def __init__(self, config: Any) -> None:
         self._patches = []  # type: List[Any]
         self._mocks = []  # type: List[Any]
         self.mock_module = mock_module = _get_mock_module(config)
-        self.patch = self._Patcher(self._patches, self._mocks, mock_module)
+        self.patch = self._Patcher(
+            self._patches, self._mocks, mock_module
+        )  # type: MockerFixture._Patcher
         # aliases for convenience
         self.Mock = mock_module.Mock
         self.MagicMock = mock_module.MagicMock
@@ -254,6 +258,63 @@ def dict(
                 **kwargs
             )
 
+        @overload
+        def __call__(
+            self,
+            target: str,
+            new: None = ...,
+            spec: Optional[builtins.object] = ...,
+            create: bool = ...,
+            spec_set: Optional[builtins.object] = ...,
+            autospec: Optional[builtins.object] = ...,
+            new_callable: None = ...,
+            **kwargs: Any
+        ) -> unittest.mock.MagicMock:
+            ...
+
+        @overload
+        def __call__(
+            self,
+            target: str,
+            new: _T,
+            spec: Optional[builtins.object] = ...,
+            create: bool = ...,
+            spec_set: Optional[builtins.object] = ...,
+            autospec: Optional[builtins.object] = ...,
+            new_callable: None = ...,
+            **kwargs: Any
+        ) -> _T:
+            ...
+
+        @overload
+        def __call__(
+            self,
+            target: str,
+            new: None,
+            spec: Optional[builtins.object],
+            create: bool,
+            spec_set: Optional[builtins.object],
+            autospec: Optional[builtins.object],
+            new_callable: Callable[[], _T],
+            **kwargs: Any
+        ) -> _T:
+            ...
+
+        @overload
+        def __call__(
+            self,
+            target: str,
+            new: None = ...,
+            spec: Optional[builtins.object] = ...,
+            create: bool = ...,
+            spec_set: Optional[builtins.object] = ...,
+            autospec: Optional[builtins.object] = ...,
+            *,
+            new_callable: Callable[[], _T],
+            **kwargs: Any
+        ) -> _T:
+            ...
+
         def __call__(
             self,
             target: str,
@@ -262,9 +323,9 @@ def __call__(
             create: bool = False,
             spec_set: Optional[builtins.object] = None,
             autospec: Optional[builtins.object] = None,
-            new_callable: Optional[builtins.object] = None,
+            new_callable: Optional[Callable[[], Any]] = None,
             **kwargs: Any
-        ) -> unittest.mock.MagicMock:
+        ) -> Any:
             """API to mock.patch"""
             if new is self.DEFAULT:
                 new = self.mock_module.DEFAULT