This article does not cite any sources. (December 2009) (Learn how and when to remove this template message)
For example, if an input field is meant to accept only integer values 0–100, then examples of boundary cases would be entering the values -1, 0, 100, and 101. A common technique for testing boundary cases is to perform three tests: one on the boundary and one on either side of it. For the previous example, this would involve testing -1, 0, 1, 99, 100, and 101.