Other teams besides Chelsea, Bayern and Leverkusen, are likely to have no trouble in these matches. Chelsea's high-budget squad and aggressive transfer policy will be a serious test for Leverkusen, and this match is the one to watch. Against opponents like Bochum, Fortuna Sittard, and Pisa, Leverkusen is highly likely to win. The Chelsea match will be a tougher test, but with Leverkusen's European experience and disciplined play, it's a match where they can at least pick up a point.
Yeah the Chelsea game will definitely be a tough test but it's just the pre season so no pressure at all and I believe Chelsea won't be playing their best players in the game, there are new players that they would want to try out and see their performance so Leverkusen will have a chance to fight back. They have lost most of their stars so there will be a void left in the squad that's why they can't compete properly as they should.
In the other games I don't think it will be a problem for them at all, these teams are easy teams they should win easily. Only the Chelsea game will be a good test for them. At least winning them will help boost their confidence and prepare them well for the league.