Testing, Validation, and Quality Assurance
What this domain tests
This domain separates verification (are we building it right?) from validation (are we building the right thing?), and tests your ability to select test levels, design test cases, and interpret results honestly.
Concepts to master
Know the levels: unit, integration, system, acceptance, and what each can and cannot catch. Understand black-box vs white-box techniques, equivalence partitioning, boundary value analysis, decision tables, and pairwise combination reduction. Distinguish regression testing from confirmation testing, and smoke from sanity. Understand defect density, escape rate, coverage (and its limits - high coverage does not imply correctness), and entry and exit criteria. Know the difference between a defect, a failure, and a fault.
Traps in questions
Common traps: treating 100% statement coverage as proof of correctness; confusing validation with verification; and choosing exhaustive testing when a designed technique gives equivalent confidence. Another trap is blaming the tester for a defect found in production - questions ask about process, not blame.
Worked rule of thumb
For any numeric input with a valid range, test the boundaries and just outside them (min-1, min, max, max+1) plus one interior value. Boundary value analysis catches the off-by-one errors that equivalence partitioning alone misses, and it is the single most reliable test-design heuristic in exams.
Quality assurance
QA is process-oriented and preventive; testing is product-oriented and detective. Questions that ask how to prevent defects point to reviews, standards, and static analysis - not to more testing.