Selective and Targeted Test Execution

Use tags/grep (--grep "@smoke", --grep "@critical") to slice suites by risk, not directory.
Filter by spec patterns (--spec "**/*checkout*") or git diff (npm run test:changed) to focus on impacted areas.
Combine priority metadata (P0–P3) with change detection to decide which levels to run pre-commit vs. in CI.
Record burn-in history for newly added specs; promote to main suite only after consistent green runs.
Document the selection strategy in README/CI so the team understands when full regression is mandatory.

Source: 32+ selective testing strategies blog, Murat testing philosophy.