property-based-testing

Generate property-based tests with Hypothesis, jqwik, or Kotest frameworks.

5|1|Updated Jun 17, 2026
One-click install
npx skills add https://github.com/roanbrasil/engineer-grade-agent-skills --skill property-based-testing-roanbrasil
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: property-based-testing
Source: https://github.com/roanbrasil/engineer-grade-agent-skills/tree/main/skills/property-based-testing
Command: npx skills add https://github.com/roanbrasil/engineer-grade-agent-skills --skill property-based-testing-roanbrasil

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Traditional example-based unit tests only cover a small set of predefined inputs, missing rare edge cases that cause production bugs in parsers, serialization, pure functions, and state machines.

Core Features & Use Cases

  • Multi-language framework support: Includes guidance for Hypothesis (Python), jqwik (Java/Kotlin), and Kotest Property (Kotlin) to match your project's tech stack.
  • Structural property validation: Test invariants, idempotence, round-trip consistency, commutativity, and oracle parity against reference implementations instead of individual input/output pairs.
  • Edge case discovery: Automatically generate hundreds of random inputs and shrink failing cases to minimal reproducible examples to speed up debugging.
  • Use case example: Verify that a JSON serializer always round-trips correctly for all valid input, or that a new optimized sorting function behaves identically to a known-correct reference implementation.

Quick Start

Use the property-based-testing skill to write a property test that validates your JSON serializer round-trips all input data correctly using the framework matching your project's programming language.

Frequently Asked Questions about property-based-testing

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How does property-based testing find edge cases missed by traditional unit tests?

Property-based testing finds edge cases by automatically generating hundreds of random inputs to validate structural invariants and round-trip consistency, rather than relying on predefined input-output pairs. It shrinks failing cases to minimal reproducible examples for faster debugging.

How do I test JSON serialization round-trips using Hypothesis or jqwik?

You can test JSON serialization round-trips by defining property assertions that automatically validate data consistency across all generated inputs. Use Hypothesis for Python or jqwik for Java and Kotlin to automatically generate valid input data and verify round-trip correctness.

Can I verify new implementation parity against a reference function with property-based testing?

Yes, property-based testing verifies implementation parity by using oracle testing against known-correct reference code. It automatically generates diverse inputs to ensure your new optimized implementation behaves identically to the reference implementation across exhaustive test cases.

Does property-based testing support Kotlin and Java tech stacks?

Property-based testing supports Kotlin and Java stacks through the jqwik and Kotest Property frameworks, while Python projects use Hypothesis. This multi-language support matches framework integration to your specific project's technology stack for defining custom input generators.

What is the best way to test state machines and pure functions for undetected bugs?

The best way to test state machines and pure functions is using property-based testing to define stateful test sequences and structural property assertions. This approach automatically generates exhaustive random inputs to uncover rare edge case bugs that slip through traditional example-based tests.