Yes they are. Provided that CDSpeed is set to the accuracy seting for transfer rate tests, a successful TRT proves absolutely that the disc is readable in that drive.

A failed TRT proves that there are reading problems, but there would still be a possibility that the drive might read the disc if given the chance to slow down and re-read sectors. That can be further investigated by e.g. a ScanDisc test.

Whether the files contain random data, video, or secret plans for building the Death Star, makes no difference.