# Boundary Value Analysis

## Overview

Let’s understand Boundary Value Analysis in this tutorial. It is a software testing technique used to find errors at the boundaries of the input value ranges.

## Boundary Value Analysis

Boundary Value Analysis(BVA) is a technique that tests the boundary values or limits of the input domain of the software. It is based on the assumption that errors are more likely to occur at the edges of the input range than in the middle. Therefore, it is crucial to test the values at or near the boundaries, such as minimum, maximum, just above, just below, or on the boundary.

BVA is a black box test design technique where test cases are designed by using boundary values. Programmers often fail to see the special processing required by the input values that lie at the boundary of the different equivalence classes. For example, programmers may improperly use < instead of <=, etc.

## Example

For example, Consider a web page with an input field that accepts numbers.

The specification for the field is: the field is supposed to accept a number from 1 to 100.

Identify the boundaries: Analyze the specified input domain for the system and identify the boundaries. This includes maximum, minimum, just inside/outside boundaries, typical values, and error values.

The tester would design the boundary value test cases as follows:

- Exact boundary values: 1 and 100
- Just below the boundary values (
**min-1**and**max-1**): 0 and 99. - Just beyond the boundary values (
**min+1**and**max+1**):2 and 101.

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