Fix deprecate f-string usage

pyiron_snippets/deprecate.py

@@ -146,7 +146,8 @@ def decorated(*args, **kwargs):
                 if kw in self.arguments:
                     warnings.warn(
                         message_format.format(
-                            "{function.__module__}.{function.__name__}({kw}={kwargs[kw]})"
+                            f"{function.__module__}.{function.__qualname__}"
+                            f"({kw}={kwargs[kw]})"
                         ),
                         category=self.category,
                         stacklevel=2,

tests/unit/test_deprecate.py

@@ -4,6 +4,15 @@
 from pyiron_snippets.deprecate import deprecate, deprecate_soon
 
 
+class ToGiveAQualname:
+    content = "this is the string"
+
+    @staticmethod
+    @deprecate(bar=f"Instead of {content}, we want to see a string")
+    def foo(bar=None, baz=None):
+        pass
+
+
 class TestDeprecator(unittest.TestCase):
     def test_deprecate(self):
         """Function decorated with `deprecate` should raise a warning."""
@@ -125,6 +134,15 @@ def food(bar=None, baz=None):
             food(baz=True)
         self.assertEqual(len(w), 2, "Not all warnings preserved.")
 
+    def test_warning_reference(self):
+        with warnings.catch_warnings(record=True) as w:
+            ToGiveAQualname.foo(bar=True)
+            self.assertIn(
+                f"{ToGiveAQualname.foo.__module__}.{ToGiveAQualname.foo.__qualname__}",
+                str(w[0].message),
+                msg="Ensure full reference to function appears in warning.",
+            )
+
 
 if __name__ == "__main__":
     unittest.main()