qa-fundamentalslisted

# QA Fundamentals ## Core distinctions (get these right, they change what you do) - **QA vs QC**: QA is process-focused, preventive ("are we building it right, with a process that prevents defects"). QC is product-focused, detective (testing the actual output). Testing is a QC activity inside a broader QA process. - **Verification vs Validation**: Verification asks "did we build the product right" (spec conformance — reviews, static analysis). Validation asks "did we build the right product" (does it satisfy the actual user need — testing against real usage). - **SDLC vs STLC**: SDLC is the whole software lifecycle (requirements→design→build→deploy→maintain). STLC is the testing-specific sub-lifecycle running alongside it: requirement analysis → test planning → test case design → environment setup → execution → closure. ## Test strategy vs test plan - **Strategy** = org/product-level, stable across releases: what testing types are mandatory, tooling standards, environments, entry/exit criteria philosophy, risk appetite. - **Plan** = per-release/per-feature, derived from strategy: specific scope, schedule, owners, this release's risk areas. ## Risk-based testing (how to prioritize when time is limited) Score each feature/area on two axes and test in priority order: - **Likelihood of failure** — new/complex code, recently changed, historically buggy area, third-party dependency. - **Impact of failure** — revenue path, data loss potential, compliance/legal exposure, blast rad