Property-Based Testing

Property-based testing checks a named rule across generated valid inputs. It complements the example-focused red-green-refactor loop in test-driven-development; it does not replace targeted examples, integration tests, or a release gate.

Scope the candidate

1. Inspect the public behavior, existing tests, and the repository's test runner before choosing a library or changing a dependency.
2. State the operation, input domain, observable result, and the business or technical rule that must always hold. If the rule cannot be stated without repeating the implementation, use example tests or refactor a seam first.
3. Choose the strongest independent oracle available: