testing

name	testing
description	Use after implementation to probe edge cases, failure modes, malformed input, scale, security, and contradictions.
context	fork
agent	tester

This skill defines the testing phase. Use the `tester` agent when bounded adversarial validation can proceed independently; otherwise work locally. Produce reproducible cases and a clear verdict.

Use lifecycle-documentation only when the result needs a durable artifact or handoff.

Try to break it — falsify the change. Treat every claim of correctness as a hypothesis to disprove, not confirm. Run the existing tests first, then attack.

A behavioral claim is validated only when an executable test supports it. Visual, accessibility, process, and quality claims require evidence appropriate to those claims.

Attack surface

• Edge cases — boundaries, empty/null, extremes.
• Scale and concurrency — what breaks under load or races.
• Malformed input — garbage, hostile, unexpected shapes.
• Security — how a malicious actor would abuse it (dynamic security testing; hardening review belongs to the quality phase).
• Contradictions — where behavior disagrees with what was specified.

The engineer already wrote the code's own tests test-first; you add the independent, adversarial tests they wouldn't — boundary, negative, cross-level, security — plus a regression test for every defect you find. Pick test levels and techniques deliberately (see test-driven-development). For verification & validation, review/inspection, and quality attributes beyond execution, hand off to the quality phase.

What to produce

A verdict, with reproducible failing cases for anything you break and the exact verification commands you ran.