1. Boundary value Analysis
Mostly in s/w defects occur due to boundaries and conditions.
Number of units bought
Price per unit (rs)
First 10 units (1-10) 5
Next ten units (11-20)
4.75
Next ten units (21-30)
4.50
More than 30 units
4.00

2. Most of the defects occur around the boundaries.
Reason
Confusion to use the <= operator or < operator.
Confusion caused by the availability of multiple ways to implement loops and condition checking.( for, while repeat loop – each of these having different terminating conditions).
Sometimes requirement may not be clearly understood especially around the boundaries.

3. Values to be tested
Why this value should be tested
Expected value of the o/p 1
Beginning of the first slab 5
Value in the first slab, removed from the boundaries 25 9
End of the first slab (or) just below the second slab 45 10
Limit for the II slab 50 16
Value in the II slab, removed from the boundaries

4. “Boundary value analysis is useful to generate test cases when the input data is made up of clearly identifiable boundaries or ranges”.