test: v4l2_compat: Report test as skipped if no compatible driver found

The V4L2 compatibility layer test includes a list of supported devices,
as V4L2 compatibility isn't officially supported with all devices yet.
If no supported device is present, the test reports success, while it
actually hasn't run. Report it being skipped in that case.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

test/v4l2_compat/v4l2_compat_test.py

@@ -147,6 +147,10 @@ def main(argv):
             print('success')
         drivers_tested[driver] = True
 
+    if len(drivers_tested) == 0:
+        print(f'No compatible drivers found')
+        return TestSkip
+
     if len(failed) > 0:
         print(f'Failed {len(failed)} tests:')
         for device in failed: