testing-rules

Behavior-based testing focuses assertions on observable outcomes and regressions rather than exact wording. You write tests that validate actual software behavior, ensuring they catch real failures while remaining resilient to minor refactors.

Proportional coverage scales testing depth to risk: new modules need full suites, bug fixes require targeted regression tests, refactors need behavioral assertions, and trivial edits often need no new tests. This prevents both gaps and bloat.

Test hygiene involves deleting noisy tests, consolidating repetitive checks, and keeping only high-value coverage that proves real behavior. Review existing tests to identify brittle assertions and unnecessary file checks that lock in implementation details.

Visual verification is required after HTML or CSS changes. You run visual checks to confirm the UI renders correctly post-refactor, then report the results clearly to document that the visual behavior remains unchanged.

Reviewing BATS suites requires checking that assertions validate observable behavior rather than implementation details. You identify silent-failure risks by ensuring tests fail loudly when behavior breaks and consolidate repetitive shell checks into high-value coverage.

Tests pass despite broken features when assertions validate wording or file structure instead of behavior. Root-cause diagnosis requires rewriting tests to assert observable outcomes, eliminating silent-failure risks by ensuring the suite fails loudly on actual regressions.