So far City have drawn with Hungarian ginats Ferencvaros, and lost in games against TUS Celle of Germany, Arsenal XI and Sheffield Utd who fielded a full strength first team.
Onuora believes the games have provided the ideal preparation ahead of the new season.
"We've had some tough games, but things are coming together well. Playing against teams like Sheffield United, who are packed with quality, can be difficult," Onuora told the Lincolnshire Echo. "They're always going to have spells in games where they are going to get on top. You get pinned back and can't get the supply to
your forwards."
Some elements of the clubs fans have begun to voice discontent without a ball being kicked in anger, possibly venting their frustrations at what they see as a quiet summer for the Imps. However Onuora believes he's seen enough to suggest the Imps can compete in League Two this season.
"There are things we still need to work on but we have produced glimpses of what we're capable of in those games and it has set us up well. I would never say any game is easy or easier, but we won't be coming up against the same calibre of opposition when the season gets underway."