Boundary Value Analysis (BVA) is a type of black box testing in which the testing of data is performed within the boundaries. In Boundary Value Analysis there are two types of boundaries: valid boundary and invalid boundary.
Boundary value analysis is the process of examining the data from the extreme ends. The boundary ends are minimum, maximum, just inside/outside. The values can be taken from any of these boundaries to test the data.
Boundary Analysis testing is used when practically it is impossible to test large pool of test cases individually. Boundary value analysis is effective when the tester knows the exact range of values.
Consider an example only 10 tickets can be ordered at one time. So the valid boundary is from 1-10 and invalid boundary is 0 and from 11 onwards. So the boundaries can be mentioned as follows:
Boundary value for invalid partition (boundary value below minimum boundary): 0
Boundary value for valid partition (Minimum boundary value): 1
Boundary value for valid partition (Maximum boundary value): 10
Boundary value for invalid partition (boundary value above maximum boundary): 11 onwards
If we select two values from the same valid partition i.e. suppose we select two values from 1-10 then the result will be same. So one value from valid partition is sufficient to test the data.
Advantages of boundary value analysis:
- Small set of test cases is prepared.
- Easy to test the boundary values.
- Provides clear guidelines to prepare the test cases.
Disadvantages of boundary value analysis:
- Difficult to prepare the test cases if the boundary values are not known correctly.
- Not useful for large amount of values.
- Not all the possible inputs are tested.