diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index 92c08b9dc6..5ea4c4df8b 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -1103,14 +1103,17 @@ def skip_if_unsupported(required_formats=(), read_only=False):
         return func_wrapper
     return skip_test_decorator
 
-def skip_for_formats(formats: Sequence[str] = ()):
+def skip_for_formats(formats: Sequence[str] = ()) \
+    -> Callable[[Callable[[QMPTestCase, List[Any], Dict[str, Any]], None]],
+                Callable[[QMPTestCase, List[Any], Dict[str, Any]], None]]:
     '''Skip Test Decorator
        Skips the test for the given formats'''
     def skip_test_decorator(func):
         def func_wrapper(test_case: QMPTestCase, *args: List[Any],
                          **kwargs: Dict[str, Any]) -> None:
             if imgfmt in formats:
-                test_case.case_skip(f'{test_case}: Skipped for format {imgfmt}')
+                msg = f'{test_case}: Skipped for format {imgfmt}'
+                test_case.case_skip(msg)
             else:
                 func(test_case, *args, **kwargs)
         return func_wrapper