Boundary Value Analysis

Introduction:

One of the most crucial step in software development is software testing, there are number of software testing technique used and boundary value analysis (BVA) is a widely used software testing for checking errors or bugs on ranges in boundaries. Equivalence partitioning plays a vital role in boundary value analysis and this both techniques are the ‘black box test design techniques.

Boundary value analysis:

‘‘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’’. Doing an analysis at the boundary values called boundary value analysis. The tester creates required test input fields by using boundary value analysis. The basic method of implementation of boundary value analysis is to keep one variable as a nominal value and other variable as its extreme value. There are two boundaries in each range called the lower boundary (starting range) and the upper boundary (end range), this will give one valid partition and two invalid partition.

Example:

A password column cannot take less that 6 and more than 24 characters.

Minimum boundary value is 6

Maximum boundary value is 24

Valid text length is 6, 7, 8 …23, 24

Invalid text length is 5, 25

Test case 1: Text length of 5 (min-1) = Invalid

Test case 2: Text length of exactly 6 (min) = Valid

Test case 3: Text length of 7 (min+1) = Valid

Test case 4: Text length of 23 (max-1) = Valid

Test case 5: Text length of exactly 24 (max) = Valid

Test case 6: Text length of 25 (max+1) = Invalid