This is the back end repo for the contractor-project marketplace app. The corresponding front end repo is here
There is one backend test to verify one par of the auto-bid logic. MarketplaceService has a method called setWinningBid. It will query the bid repository for the two lowest bids, which are indexed by lowest price for efficiency. If there are two bids, and they're not equal, and they're not 0, it will awart the project to the lowest minimum bid amount from the lowest bidder, but at a price that is one penny lower than the 2nd lowest minimum bid. So it doesn't autobid all the way down to their floor price, it only goes down as far as what would take to have them win.