Till now we have understood that exhaustive testing is not possible, I mean testing each any every field with each and every possible combination of input is not possible. So experts have come up with different techniques of black box testing. Out of which we have already gone through Equivalence partitioning and in this post we will discuss one of the best and widely used test case design technique called boundary value analyses. We used different techniques to select the important test cases in the intelligent way from a pool of test cases so that we cover all the scenario. Boundary value analysis is one of this technique.
BVA is a black box test design technique which test application at its boundary instead of the center of input. Most of the defect lies on the boundary of the input field, so it make sense to test the application fields at their lower value or upper value / small value or bigger value / Starting value or end value. Boundary Value is valued which lie on the boundary of an equivalence partitioning.
Every input filled have valid input and invalid input, so we design test cases for both inputs, valid and invalid. BVT is quite effective when we use this technique with Equivalence Partitioning and you can use this technique with all level of testing.
Example: Let us consider the input text box which accepts age in the range of 18 to 60. So we can create three partitions as below.
Invalid Partition Valid Partition Invalid Partition
- Very useful for identifying the user interface defects.
- The concept is clear and any new bee can start writing test cases using this technique.
- Small and effective set of test cases can be defined.
- It is not possible to test all possible condition
- Depending defects cannot be identified with this technique