Mid-LevelQA Methodology & Strategy
How do you test error handling and edge cases systematically?
- edge cases
- boundary testing
- error handling
- test design
Answer it first, then compare. Nothing here is saved or scored.
Model answer
Techniques: (1) Boundary value analysis: test at limits (0, 1, max, max+1). (2) Equivalence partitioning: group inputs into classes and test one from each. (3) Error guessing: based on experience, what typically breaks? (4) Negative testing: invalid inputs, empty fields, SQL injection, XSS payloads. (5) State transition testing: test all valid and invalid state changes. (6) Network failures: offline, slow connection, timeout. (7) Concurrent access: two users editing the same record. (8) Resource exhaustion: disk full, memory low. Document edge cases in a shared catalog so the whole team can reference them.
What interviewers listen for
- Risk-based prioritisationYou can defend skipping coverage on a path because the risk maths supports it.
- Test design fluencyYou apply equivalence partitioning and decision tables to concrete inputs in real time.
- Metric judgmentYou distinguish between metrics that drive learning and metrics that drive theatre.
- Strategy under constraintYou can produce a defensible plan when the team has half the time and twice the scope.