Improve StrictMock guidance for undefined callables

tests/strict_mock_testslide.py

@@ -531,7 +531,9 @@ def raises_when_an_undefined_method_is_accessed(self):
                                     UndefinedAttribute,
                                     f"'{self.test_method_name}' is not set.\n"
                                     f"{self.strict_mock_rgx} must have a value set "
-                                    "for this attribute if it is going to be accessed.",
+                                    "for this attribute if it is going to be accessed.\n"
+                                    r"Tip: use testslide.mock_callable\(\) to configure "
+                                    "this attribute.",
                                 ):
                                     getattr(self.strict_mock, self.test_method_name)
 
@@ -863,6 +865,18 @@ async def raises_when_setting_a_non_callable_value(self):
                         ):
                             setattr(self.strict_mock, self.method_name, "not callable")
 
+                    @context.example
+                    async def raises_when_an_undefined_method_is_accessed(self):
+                        with self.assertRaisesWithRegexMessage(
+                            UndefinedAttribute,
+                            f"'{self.method_name}' is not set.\n"
+                            "<StrictMock .+> must have a value set "
+                            "for this attribute if it is going to be accessed.\n"
+                            r"Tip: use testslide.mock_async_callable\(\) to configure "
+                            "this attribute.",
+                        ):
+                            getattr(self.strict_mock, self.method_name)
+
                     @context.sub_context
                     def signature_and_type_validation(context):
                         @context.shared_context

testslide/core/strict_mock.py

@@ -826,7 +826,19 @@ def __setattr__(self, name: str, value: Any) -> None:
 
     def __getattr__(self, name: str) -> Any:
         if self._template and self.__template_has_attr(name):
-            raise UndefinedAttribute(self, name)
+            template_value = getattr(self._template, name, None)
+            if inspect.iscoroutinefunction(template_value):
+                message = (
+                    "Tip: use testslide.mock_async_callable() to configure "
+                    "this attribute."
+                )
+            elif callable(template_value):
+                message = (
+                    "Tip: use testslide.mock_callable() to configure this attribute."
+                )
+            else:
+                message = None
+            raise UndefinedAttribute(self, name, message)
         else:
             raise AttributeError(f"'{name}' was not set for {repr(self)}.")