Boundary Value Analysis is a black box test design technique where test case are designed by using boundary values, BVA is used in range checking.
BVA is a test case design technique to test boundary value between partitions. A boundary value is an input or output value on the border of an equivalence partition, includes minimum and maximum values at inside and outside boundaries.
BVA has recognized that input values at the extreme ends of input domain cause more errors in the system. More application errors occur at the boundaries of input domain. ‘Boundary value analysis’ testing technique is used to identify errors at boundaries rather than finding those exist in the center of input domain.
For Example :
Suppose you are testing Password functionality of your application that accepts minimum 8 characters and maximum 15 characters long. So Valid range 8-15, Invalid range 7 or less than 7 and Invalid range 15 or more than 15.
Test Cases for Valid partition value, Invalid partition value, and exact boundary value.
Test Cases 1: Consider password length less than 8(7 or less than 7) .
Test Cases 2: Consider password of length exactly 8.
Test Cases 3: Consider password of length between 9 and 14.
Test Cases 4: Consider password of length exactly 14.
Test Cases 5: Consider password of length more than 15(16 or greater).