I challenge anyone to try building a C compiler without a big suite of tests. Zig is the most recent attempt and they had an extensive test suite. I don't see how that is disqualifying.

If you're testing a model I think it's reasonable that "clean room" have an exception for the model itself. They kept it offline and gave it a sandbox to avoid letting it find the answers for itself.

Yes the compression and storage happened during the training. Before it still didn't work; now it does much better.