Properties of Good Tests

When writing test vectors in cookbook artifacts (ingredients and recipes), each test vector should exhibit these properties — adapted from Kent Beck's Test Desiderata.

For test vectors in cookbook artifacts

1. Isolated — each test vector MUST be independent; no shared mutable state or ordering dependency between vectors
2. Deterministic — the expected result MUST be unambiguous; the same input always produces the same output
3. Behavioral — test vectors SHOULD verify what the component does, not how it does it internally
4. Specific — each vector SHOULD target one behavior or edge case; a failure points to exactly one cause
5. Readable — a test vector MUST clearly communicate what it tests and what the expected outcome is
6. Predictive — the set of test vectors SHOULD be sufficient to catch real bugs; if all vectors pass, the implementation is likely correct

Less relevant for cookbook authoring

The remaining Beck desiderata (fast, composable, writable, automated, structure-insensitive, inspiring) apply to the generated test code, not to the test vector specifications in cookbook artifacts. They are covered by the implementing and testing use cases.

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