Like all other Gyms in Paldea, the Montenevera Gym building itself is simply used for registering Gym challengers. The Gym Test and Gym battle are both conducted outside the building, on Ryme's concert stage. Additionally, all battles at the Montenevera Gym are Double Battles.
Gym Test
The Gym Test requires the player to defeat the Montenevera Gym Trainers in consecutive Double Battles. The player's Pokémon are automatically healed in-between battles.
Ryme is faced in a Double Battle. Certain actions during the battle will cause the spectators to cheer for either Trainer. This causes the Pokémon from the supported side to receive stat boots in one or more of their stats. Ryme will Terastallize her Toxtricity at the first opportunity.
The Montenevera Gym first appeared in HZ061. Roy sought to battle Ryme there for his second Terastal Training test, but she wasn't present when he and his friends arrived at the Gym. After Roy had defeated MC Sledge on the stage outside the Gym, Ryme arrived and allowed Roy to challenge her after a brief rap battle between the two. During the match, Roy used his usual tactic of firing Fuecoco up with their song, which allowed them to defeat Ryme's Houndstone. However, Ryme's Toxtricity easily deflected every attack thrown in its way with its Punk Rock-boosted sound moves. Roy eventually grew desperate enough to Terastallize Fuecoco on the spot, but he still lost, without Ryme even having to resort to Terastallizing her own Pokémon. Deeming that Roy had Terastallized out of desperation and that he was unable to draw out his partner's full potential, Ryme declared that Roy had failed the test, much to his dismay.
In HZ062, Roy returned to the stage and requested to have a rematch with Ryme so he could have another shot at passing his test. Ryme accepted and declared that the match would be a special one-on-one battle, with her Toxtricity against Roy's Fuecoco. Thanks to Roy's refined battle style and singing tactic, he was able to gain the upper hand in the match, even getting the crowd watching the battle to join in on the singing. This time, Ryme saw it fit to use Terastallization herself. Roy also Terastallized Fuecoco and won the battle soon after. He explained that he had remembered how to sing to connect with his Pokémon as opposed to simply using singing to win. In recognition of Roy having understood the true meaning of singing, Ryme allowed him to pass the test and told that it would be up to Roy if Fuecoco could realize his full potential.
In HZ062, Toxtricity was used against Fuecoco in a one-on-one rematch. This time, Fuecoco was able to deal significant damage to it thanks to his newfound singing and battle tactics, forcing Toxtricity to Terastallize. Fuecoco Terastalized soon after and managed to defeat Toxtricity, winning Roy the rematch and passing his test.
