ISTQB-CTFL Exam - Topic 3 Question 50 Discussion

The correct outcome of a two-value boundary value analysis applied to the password length is the set of test cases represented by option D. Boundary value analysis is a test design technique that focuses on the values at the boundaries of an equivalence partition, such as the minimum and maximum values, or the values just above and below the boundaries. A two-value boundary value analysis uses two values for each boundary, one representing the valid value and one representing the invalid value. For example, if the valid range of values is from 4 to 7, then the two values for the lower boundary are 3 and 4, and the two values for the upper boundary are 7 and 8. The test cases in option D use these values for the password length, while also satisfying the other requirements of the password, such as containing at least one numeric character, one capital letter, and one lowercase letter. The test cases in option D are:

1RhT: a 4-character password that is valid

rSp53: a 5-character password that is valid

3N3e10: a 6-character password that is valid

8sBdby: an 8-character password that is invalid The test cases in the other options are incorrect, because they either use values that are not at the boundaries of the password length, or they do not meet the other requirements of the password. For example, the test cases in option A are:

1xA: a 3-character password that is invalid, but it does not contain a capital letter

aB11: a 4-character password that is valid

Pq1ZZab: a 7-character password that is valid

7iDD0a1x: an 8-character password that is invalidReference: ISTQB Certified Tester Foundation Level (CTFL) v4.0 sources and documents:

ISTQB Certified Tester Foundation Level Syllabus v4.0, Chapter 2.2.1, Black-box Test Design Techniques1

ISTQB Glossary of Testing Terms v4.0, Boundary Value Analysis, Equivalence Partition2