Question 40 - CTFL4 discussion

Boundary value analysis is a technique that tests boundary values between partitions of equivalent data. Boundary values are values at the edge of an equivalence partition or at the smallest incremental distance on either side of an edge. Boundary value analysis can be applied to both input and output values. Based on the given requirement, we can identify two input values: age and weekend. Age should be an integer of 0 or above, and weekend means Friday to Sunday inclusive. The following statement is not correct:

A) Thursday is a valid input boundary value. This statement is not correct, as Thursday is not a boundary value for the input weekend. The boundary values for the input weekend are Friday and Sunday, as they are at the edge of the equivalence partition that represents weekend days. The following statements are correct:

B) A minimum of 6 valid test cases are derived from boundary value analysis based on input age. This statement is correct, as we can derive six valid test cases based on input age by using the minimum and maximum values for each equivalence partition defined by the requirement. The equivalence partitions for input age are: under 7 (0 to 6), 7 to 13 inclusive (7 to 13), and greater than 65 (66 and above). The minimum and maximum values for each partition are: 0 and 6, 7 and 13, and 66 and any value above it.

C) $3.01 is a valid output boundary value. This statement is correct, as $3.01 is a boundary value for the output additional fee. The additional fee can have four possible values depending on the input age: $0 (for visitors aged under 7), $2.40 (for visitors aged 7 to 13 inclusive with a 20% discount), $1.50 (for visitors aged greater than 65 with a 50% discount), and $3 (for visitors aged between 14 and 65). The boundary values for the output additional fee are $0 and $3, as they are at the edge of an equivalence partition or at the smallest incremental distance on either side of an edge. Therefore, $3.01 is a valid output boundary value, as it is at the smallest incremental distance above $3.

D) 7 and 13 are boundary values for the equivalence partition including age 10. This statement is correct, as 7 and 13 are boundary values for the equivalence partition that represents visitors aged 7 to 13 inclusive. This partition includes age 10, which is an internal value within the partition. Verified

Reference: [A Study Guide to the ISTQB Foundation Level 2018 Syllabus - Springer], Chapter 4, page 37-38.