Property-Based Testing Skill

A Claude Code skill that provides guidance for property-based testing (PBT) across multiple programming languages and smart contract development.

What This Skill Does

When activated, this skill helps Claude:

• Detect PBT opportunities - Recognizes patterns like encode/decode pairs, validators, normalizers, pure functions, and smart contract invariants
• Generate property-based tests - Creates tests with appropriate strategies, properties, and edge cases
• Review existing PBT tests - Identifies issues like tautological properties, vacuous tests, and weak assertions
• Design with properties - Uses Property-Driven Development to define specifications before implementation
• Refactor for testability - Suggests code changes that enable stronger property testing

Supported Languages

Smart Contract Testing

See secure-contracts.com for tutorials.

File Structure

property-based-testing/
├── SKILL.md           # Entry point - detection patterns and routing
├── README.md          # This file
└── references/
    ├── generating.md  # How to write property-based tests
    ├── reviewing.md   # How to evaluate test quality
    ├── strategies.md  # Input generation reference
    ├── design.md      # Property-Driven Development workflow
    ├── refactoring.md # Making code more testable
    └── libraries.md   # PBT library reference by language

Usage

The skill activates automatically when Claude detects relevant patterns:

• Serialization pairs (encode/decode, serialize/deserialize)
• Validators and normalizers
• Pure functions with clear input/output types
• Data structure operations
• Smart contracts (Solidity/Vyper)

You can also invoke it explicitly by asking Claude to use property-based testing.

Example Prompts

"Write property-based tests for this JSON serializer"
"Review this Hypothesis test for quality issues"
"Help me design this feature using properties first"
"This function is hard to test - how can I refactor it?"
"Write Echidna invariants for this token contract"

Property Quick Reference