spec-testability-heuristics

What testability means here

ISTQB defines testability as "the degree to which test conditions can be established for a component or system, and tests can be performed to determine whether those test conditions have been met" (ISTQB Glossary, testability). A sentence from which no test condition can be established is not a weak requirement, it is an untestable one, and no downstream tooling fixes it.

Applying the rubric before implementation starts is the shift left approach. A requirement rewritten during review costs a sentence; the same requirement discovered as untestable after the code lands costs a rewrite, a re-implementation, and a re-review.

What this skill judges, and what it does not