What is Boundary Testing?

Boundary testing is to make sure software accepts valid data inside the valid Boundary and rejects invalid data outside the valid Boundary. A simple example would be testing the input field limitation from 0 to 100 where the lower boundary is 0 and the higher boundary is 100. We make sure we can’t go lower than 0 and higher than 100. We only test the edges and not the middle. Boundary value testing can be very beneficial since errors are frequently made during programming of the different cases near the ‘edges’ of the range of values