It's a bit confusing but test_enum_media_types() is for testing some behaviour related to the enumerator; the media type itself is already tested in test_media_types() and the new tests should go there instead. 5/6: ``` + subtype = mts[0]->subtype.Data1; + if (subtype == MEDIASUBTYPE_RGB8.Data1) + bytes_per_pixel = 1; ``` That's... odd, I can only assume you're trying to do a more 'optimized' comparison, but I don't think optimization matters here; it would be more idiomatic to just use IsEqualGUID() on the whole thing. 6/6: ``` + if (!IsEqualGUID(&enum_media_types->stream->mt.subtype, &GUID_NULL)) ``` That's not how to check if the pin is connected. It works, but it's not declarative. -- https://gitlab.winehq.org/wine/wine/-/merge_requests/10677#note_136576