I had a few questions regarding boundary value analysis, that I was hoping someone could help me with.
The first is - when should you assume to use two and three value methods of BVA
? Is there any actual distinction as to when you should use one or the other, or does it depend on the specific question asked (in terms of an examination) and I would simply need to just know how to use both? Is there a default method to use?
Secondly, consider this possible question:
A smart home app measures the average temperature in the house and provides feedback to the occupants for different average temperature ranges:
• Up to 10 C – Icy cool!
• 11 C to 15 C - Chilled out!
• 16 C to 19 C - Cool man!
• 20 C to 22 C –Too warm!
• Above 22 C - Hot and Sweaty!
Apply 3 point BVA to the above temperature ranges. How many test cases would you consider?
The answer that was provided was that:
For 10 - we would test 9, 10, 11.
For 11 - we would test 10 (already tested), 11 (already tested), 12
For 16 - we would test 15, 16, 17
For 20 - we would test 19, 20, 21
For 22 - we would test 21 (already tested), 22, 23
This would result in a a total of 12 test cases.
Can somebody please explain to me as to why we would test the upper boundary in the first partition (10 degrees), but not the upper boundaries in other valid partitions (such as 15, which would lead to us testing 14,15,16 or 19 leading to testing 18,19,20). Is this because the boundary of 10 is the only boundary within that partition, as the lower boundary is open?
As a follow on, assume that the boundaries were instead:
• 0 C to 10 C – Icy cool!
• 11 C to 15 C - Chilled out!
• 16 C to 19 C - Cool man!
• 20 C to 22 C –Too warm!
• 23 - 40 C - Hot and Sweaty!
Would the values that are tested then change to the below? Would we still need to test the upper boundary in the first partition, or would we now ignore this as we have a lower boundary value?
For the lower invalid partition -2, -1, 0
For the first valid partition: -1, 0, 1
For the second valid partition: 10, 11, 12
For the third valid partition: 15, 16, 17
For the fourth valid partition: 19, 20, 21
For the fifth valid partition: 22, 23, 24
For the upper invalid partition: 40, 41, 42
I think I have been over complicating things in my head and wracking my brain over this!
Any ideas?