WHAT IS BOUNDARY VALUE ANALYSIS?
It is the seventh article in the series of test cases in which we discuss the Boundary Value Analysis test case design method with simple examples for easy understanding.
It has been observed that programs that work correctly for a set of values in an equivalence class fail on some special values. These values often lie on the boundary of the equivalence class. It is for this reason Boundary Value Analysis has been developed as a testing technique.
The Boundary Value Analysis is a test case design technique that complements Equivalence Partitioning. In boundary value analysis, input for a test case is chosen from an equivalence class, such that the input lies at the edge of the equivalence classes. Boundary values for each equivalence class, including the equivalence classes of the output, should be covered.
Boundary value test cases are also called “Extreme Cases”. Therefore, we can say that a boundary value test case is a set of input data that lies on the edge or boundary of a class of input data or that generates output that lies at the boundary of a class of output data.
Guidelines for the Boundary Value Analysis are similar in many respects to Equivalence Partitioning. You can say that Boundary Value Analysis is the next part of Equivalence Partitioning for designing test cases where test cases are selected at the edges of the equivalence classes.
Example 1:
Test cases for input box accepting numbers between 1 and 500 using Boundary value analysis:
Test Cases for Valid partition value, Invalid partition value, and exact boundary value from the above example are given below:
1. Test Cases: with test data exactly as the input boundaries of input domain i.e. values 1 and 500 in our case.
2. Test Cases: test data with values just below the extreme edges of input domains i.e. values 0 and 499.
3. Test Cases: test data with values just above the extreme edges of the input domain i.e. values 2 and 501.
Example 2:
Assume you are testing the Login form of a website that accepts valid User Names and Passwords and accepts a minimum of 8 characters and a maximum of 14 characters. Valid range 8 to 14, 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 from the above example are given below:
1. Test Cases: Consider password length less than 8.
2. Test Case: Consider password of length exactly 8.
3. Test Cases: Consider passwords of length between 9 and 13.
4. Test Case: Consider password of length exactly 14.
5. Test Cases: Consider passwords of length more than 14.
In short Boundary Value Analysis is a test case writing technique in which test cases are selected at the edge of the equivalence classes. Stay tuned with us for upcoming articles on test cases and don’t forget to post your questions and queries in the comments.
