Gems2rom

gems2rom (another mirror here) is a program that can create a playable jukebox ROM from a game's GEMS driver files as produced by GemsScan. These jukeboxes are acceptable sources of rips, and easy to create for non-hackers.

It isn't necessarily better than an in-game sound test; for one reason, you must manually set the tempo of tracks that use a different tempo from the default (128), and tracks that dynamically change tempo could be a problem. But if there are no such songs and no in-game sound tests (or there are songs that can't be reached without hacking), that's no issue.

Another, smaller caveat is that gems2rom uses the GEMS 2.8 engine even for games that used 2.0. The difference, if any, is perfectly acceptable for VGMRips packs, even if it may result in some playback differences due to bug fixes in the engine. But if this troubles you, you can ensure complete accuracy by hacking the game to rip the songs.