iotests: Fix incomplete type declarations

We need to fix only a few places so that iotests.py can pass
mypy --disallow-incomplete-defs, which seems to be a desirable option to
have enabled in the long run.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20200511163529.349329-2-kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/iotests.py

@@ -1040,7 +1040,7 @@ def _verify_cache_mode(supported_cache_modes: Sequence[str] = ()) -> None:
     if supported_cache_modes and (cachemode not in supported_cache_modes):
         notrun('not suitable for this cache mode: %s' % cachemode)
 
-def _verify_aio_mode(supported_aio_modes: Sequence[str] = ()):
+def _verify_aio_mode(supported_aio_modes: Sequence[str] = ()) -> None:
     if supported_aio_modes and (aiomode not in supported_aio_modes):
         notrun('not suitable for this aio mode: %s' % aiomode)
 
@@ -1087,7 +1087,8 @@ def skip_if_unsupported(required_formats=(), read_only=False):
     '''Skip Test Decorator
        Runs the test if all the required formats are whitelisted'''
     def skip_test_decorator(func):
-        def func_wrapper(test_case: QMPTestCase, *args, **kwargs):
+        def func_wrapper(test_case: QMPTestCase, *args: List[Any],
+                         **kwargs: Dict[str, Any]) -> None:
             if callable(required_formats):
                 fmts = required_formats(test_case)
             else:
@@ -1097,9 +1098,8 @@ def func_wrapper(test_case: QMPTestCase, *args, **kwargs):
             if usf_list:
                 msg = f'{test_case}: formats {usf_list} are not whitelisted'
                 test_case.case_skip(msg)
-                return None
             else:
-                return func(test_case, *args, **kwargs)
+                func(test_case, *args, **kwargs)
         return func_wrapper
     return skip_test_decorator