CSS CS Optional — Paper-I, Section-B, Topic V.
🔥 Frequency: appeared in 4 of last 7 papers (2020, 2021, 2022, 2024, 2025).
🔑 Black-Box vs White-Box
| Black-Box |
White-Box (glass-box) |
| Tests against spec |
Tests internal logic paths |
| No knowledge of code |
Full knowledge of code |
| Equivalence partitioning, boundary value analysis |
Statement/branch/path coverage |
| Catches missing-functionality/spec-mismatch |
Catches logic/path errors |
- Neither is "better" — depends on defect type.
📌 Testing Levels (in order)
- Unit → individual components in isolation
- Integration → interactions between combined modules
- System → complete system vs overall requirements
- Acceptance → validates against customer's requirements (not the spec)
📌 Other Named Testing Types
- Regression — re-run tests after a change.
- Performance — speed, responsiveness, load stability.
- Web application testing — functional + usability + cross-browser + load + security.
📌 Test Design Techniques
- Black-box: equivalence partitioning, boundary value analysis, decision tables, state transition.
- White-box: statement/branch/path coverage.
🔥 Past Papers
- 2022 Q7(b) — black-box vs white-box
- 2022 Q8(a) — web application testing