fix: Add support for pytest-mock spy method fixing the SignatureAdapter (#392)

Author: fgmacedo

docs/releases/2.1.1.md

@@ -0,0 +1,8 @@
+# StateMachine 2.1.1
+
+*Not released yet*
+
+## Bugfixes in 2.1.1
+
+- Fixes [#391](https://github.com/fgmacedo/python-statemachine/issues/391) adding support to
+  [pytest-mock](https://pytest-mock.readthedocs.io/en/latest/index.html) `spy` method.

docs/releases/index.md

@@ -15,6 +15,7 @@ Below are release notes through StateMachine and its patch releases.
 ```{toctree}
 :maxdepth: 1
 
+2.1.1
 2.1.0
 2.0.0
 

poetry.lock

@@ -45,6 +45,7 @@ pre-commit = "^2.21.0"
 mypy = "^0.991"
 black = "^22.12.0"
 pdbpp = "^0.10.3"
+pytest-mock = "^3.10.0"
 
 [tool.poetry.group.docs.dependencies]
 Sphinx = "4.5.0"

pyproject.toml

@@ -25,6 +25,16 @@ def __call__(self, *args: Any, **kwargs: Any) -> Any:
         ba = self.bind_expected(*args, **kwargs)
         return self.method(*ba.args, **ba.kwargs)
 
+    @classmethod
+    def from_callable(cls, method):
+        if hasattr(method, "__signature__"):
+            sig = method.__signature__
+            return SignatureAdapter(
+                sig.parameters.values(),
+                return_annotation=sig.return_annotation,
+            )
+        return super().from_callable(method)
+
     def bind_expected(self, *args: Any, **kwargs: Any) -> BoundArguments:  # noqa: C901
         """Get a BoundArguments object, that maps the passed `args`
         and `kwargs` to the function's signature.  It avoids to raise `TypeError`

statemachine/signature.py

@@ -0,0 +1,25 @@
+from statemachine import State
+from statemachine import StateMachine
+
+
+def test_minimal(mocker):
+    class Observer:
+        def on_enter_state(self, event, model, source, target, state):
+            ...
+
+    obs = Observer()
+    on_enter_state = mocker.spy(obs, "on_enter_state")
+
+    class Machine(StateMachine):
+        a = State("Init", initial=True)
+        b = State("Fin")
+
+        cycle = a.to(b) | b.to(a)
+
+    state = Machine().add_observer(obs)
+    assert state.a.is_active
+
+    state.cycle()
+
+    assert state.b.is_active
+    on_enter_state.assert_called_once()