Boundary Value Analysis

What is boundary value analysis?

Boundary value analysis is a black-box testing technique, closely associated with equivalence class partitioning. In this technique, we analyze the behavior of the application with test data residing at the boundary values of the equivalence classes.

Example

Considering the same example we used in equivalence partitioning tutorial - an application that accepts a numeric number as input with value between 10 to 100.
We identified different equivalence classes, out of which one of the valid equivalence classes was - integer with values ranging from 10 to 100. Now, for this equivalence class our boundary values would be {10, 100}. Similarly, we can find the values at the edges of the equivalence classes to create set of test data for the boundary value analysis.

Advantages of boundary value analysis

  1. It is easier and faster to find defects as the density of defects at boundaries is more.
  2. The overall test execution time reduces as the number of test data greatly reduces.

Disdvantages of boundary value analysis

  1. The success of the testing using boundary value analysis depends on the equivalence classes identified, which further depends on the expertise of the tester and his knowldege of application. Hence, incorrect identification of equivalence classes leads to incorrect boundary vlaue testing.
  2. For application with open boundaries or application not having one dimensional boundaries are not suitable for boundary value analysis. In those cases, other black-box techniques like "Domain Analysis" are used.