|This article does not cite any references or sources. (December 2009)|
Boundary case is a frequently used term in software engineering to refer to the behavior of a system when one of its inputs is at or just beyond its maximum or minimum limits. It is frequently used when discussing software testing.
For example, if an input field is meant to accept only integer values 0–100, entering the values -1, 0, 100, and 101 would represent the boundary cases. A common technique for testing boundary cases is with three tests: one on the boundary and one on either side of it. So for the previous example that would be -1, 0, 1, 99, 100, and 101.