#testdesign

TL;DR: You should prove a risky idea can fail, then prove its refusal, in a disposable prototype...

TL;DR: A security check that treats a missing required file as nothing to check can let...

Example-based tests encode cases an agent can enumerate and hardcode past. Property-based tests quantify over inputs the agent did not see at code-write time, which is the gap that makes the lookup-table attack more expensive than the honest fix. Properties are one layer in the enforcement stack, not the whole stack.

TL;DR: A race test proves nothing unless its operations overlap and the test fails against broken...

TL;DR: A watchdog fixes a stall only when timeout errors are terminal and non-retryable; idle and...

TL;DR: An agent harness cannot independently approve work when it controls both the artifact and the...

TL;DR: Unit tests missed nine CLI journey defects; run the tool from zero state, using only its...

TL;DR: Signed, subject-bound evidence can still prove the wrong action; bind each claim to the exact...

TL;DR: You cannot call a change better because you watched it work once; freeze the comparison and...

TL;DR: Exit code zero does not prove required tests ran; compare structured outcomes against a frozen...

TL;DR: A test can pass without executing the control it names; mutation and path coverage found 59...

Teams that want their agent to do TDD reach for the instruction file. The TDAD paper measured this directly: adding a 'do TDD' instruction raised regressions by nearly two-thirds. Contextual test discovery cut them by seventy percent. The instruction is theatre. The codebase's test surface is the discipline.