How to determine if hardwoods are under cabinets?
If it is an older house with existing hardwood floors, there is a terrific chance of the floor going under the cabs, If there is laminate flooring, The chances are nil it goes under. 

On older homes, with hardwood floors if the cabinets are removed, they may need to be refinished anyway since the floors usually are never sanded and stained under the cabinets, but it beats a tie in and refinish. On newer homes, I have seen cabinets placed on the subfloor or on plywood to raise them up, and the flooring run to the cabinets.

With laminate floors, if you can find the flooring still, you will need to pull a piece to match it up by. This will have to be done anyway to some degree to tie in the new with the old, if that is what you have. You could try to patch the immediate area, which I do not recommend. I would pull up the flooring to the affected area and relay the new to recover the cabinet's foot print.