Question 7 of 8

Question 7 (10 marks)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

Given. The authentication subsystem's declared interface constraints (the specification, not the implementation): login length ∈ [6, 8] characters; password length ∈ [6, 8] characters AND must contain at least one lower-case letter, at least one upper-case letter, and at least one digit.

Find. A black-box test suite, derived purely from these stated constraints, that exercises every equivalence class and every length boundary for both the login and the password fields.

Approach. Apply equivalence partitioning to the length constraint (too-short / valid / too-long, for both fields) and to the password's three required character classes (missing lower-case / missing upper-case / missing digit), then apply boundary value analysis to the length limits (exactly 6, exactly 8, one below, one above).

1. Test case 1 — valid baseline (both fields valid, all password classes present). Login alice1 (6 chars), password Abc123 (6 chars, has lower/upper/digit).
   login = "alice1", password = "Abc123"
   Expected result: accepted — the reference case every other test case is compared against.
2. Test case 2 — login too short. Login equivalence class: length < 6.
   login = "bob" (3 chars), password = "Xyz789"
   Expected result: rejected — login shorter than the 6-character minimum.
3. Test case 3 — login too long. Login equivalence class: length > 8.
   login = "alice123456" (11 chars), password = "Xyz789"
   Expected result: rejected — login longer than the 8-character maximum.
4. Test case 4 — login at the lower length boundary (BVA). Login exactly 6 characters, the declared minimum.
   login = "abcdef" (6 chars), password = "Ab1defg"
   Expected result: accepted — 6 is exactly the boundary, not below it.
5. Test case 5 — login at the upper length boundary (BVA). Login exactly 8 characters, the declared maximum.
   login = "abcdefgh" (8 chars), password = "Ab1defgh"
   Expected result: accepted — 8 is exactly the boundary, not beyond it.
6. Test case 6 — password too short. Password equivalence class: length < 6.
   login = "carol1", password = "Ab1de" (5 chars)
   Expected result: rejected — password shorter than the 6-character minimum, independent of its character content.
7. Test case 7 — password too long. Password equivalence class: length > 8.
   login = "carol1", password = "Ab1defghi" (9 chars)
   Expected result: rejected — password longer than the 8-character maximum.
8. Test case 8 — password missing an upper-case letter. Length is valid (7 chars); character-class equivalence class: no upper-case.
   login = "dave12", password = "ab1defg"
   Expected result: rejected — violates the "must contain an upper-case letter" rule even though the length is valid.
9. Test case 9 — password missing a lower-case letter. Length is valid (7 chars); character-class equivalence class: no lower-case.
   login = "erin123", password = "AB1DEFG"
   Expected result: rejected — violates the "must contain a lower-case letter" rule.
10. Test case 10 — password missing a digit. Length is valid (7 chars); character-class equivalence class: no digit.
    login = "frank12", password = "Abcdefg"
    Expected result: rejected — violates the "must contain a number" rule.