Rules for MotoGP testing are kinda more relaxed than in F1. Riders that are contracted for racing can't test throughout the season other than on official test sessions (last year it was pre-season in Qatar, at Catalunya after the race weekend, in Misano and after the last race in Jerez). They can train though, but they have to use road going bikes with only allowed modifications being those to make it safer for the track (like removing mirrors, lights and license plates, slick tires etc.).
Test riders, on the other hand, can test race bikes throughout the season, but teams have to nominate up to 3 tracks before the season and they only can run on those 3 that they have nominated. This is the list of nominated tracks by manufacturers for this season:
KTM – Red Bull Ring, Jerez, Aragon
Ducati – Mugello, Jerez, Misano
Honda – Motegi, Jerez, Misano
Suzuki – Motegi, Jerez, Aragon
Yamaha – Motegi, Jerez, Aragon
Aprilia, due to its weak results, still has its concessions so they are allowed to test freely on any track with both test and race riders. There are still rules that limit how close to the race weekend they can be on the same track (I can't remember now if it is 2 weeks or a month)