Lot size larger than volume of bar in backtesting, won’t execute trade

So I am having an issue where when our calculated lot size is greater than the volume of that bar for the backtest, it wont execute that trade, is there anyway to force the trade or disregard the volume so that it will do it during the backtest. i am using market orders so theoretically we should always get filled, and the backtest won’t be as accurate if we are missing trades due to this. Any one have any idea on this? Thanks in advance