Boundary value analysis - TwoGears/hakomo-guides GitHub Wiki

Boundary value analysis is another black box test design technique and it is used to find the errors at boundaries of input domain rather than finding those errors in the centre of input. Equivalence Partitioning and Boundary value analysis are linked to each other and can be used together at all levels of testing. Based on the edges of the equivalence classes, test cases can then be derived.Each boundary has a valid boundary value and an invalid boundary value. Test cases are designed based on the both valid and invalid boundary values. Typically, we choose one test case from each boundary.Finding defects using Boundary value analysis test design technique is very effective and it can be used at all test levels. You can select multiple test cases from valid and invalid input domains based on your needs or previous experience but remember you do have to select at least one test case from each input domain.
Let’s take example to understand the Boundary value analysis concept:
If one application is accepting input range from 1 to 100, using equivalence class we can divide inputs into the classes, for example, one for valid input and another for invalid input and design one test case from each class.

• One test case for exact boundary values of input domains each means 1 and 100.
• One test case for just below boundary value of input domains each means 0 and 99.
• One test case for just above boundary values of input domains each means 2 and 101.