proptest

Verify Rust code invariants with property-based testing using proptest.

Updated Jan 25, 2026

Search Tags:#rust #property-based testing #proptest #shrinking #arbitrary data #test strategies

Ready to run

npx skills add https://github.com/patrykgz/rust-devagent-loop-template --skill proptest

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: proptest
Source: https://github.com/patrykgz/rust-devagent-loop-template/tree/main/.claude/skills/proptest
Command: npx skills add https://github.com/patrykgz/rust-devagent-loop-template --skill proptest

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

Property-based testing helps ensure correctness by verifying invariants across various inputs and shrinking failing cases to minimal examples.

Core Features & Use Cases

Property-based testing of Rust code using proptest, generating arbitrary data with strategies.
Shrinking: automatically reduces failing inputs to minimal counterexamples for easier debugging.
Optional: derive Arbitrary using proptest-derive for custom types.
Use Case: ensure a function behaves correctly for edge values across many inputs.

Quick Start

Write a proptest-based test that asserts a property holds for arbitrary inputs using the proptest! macro.

Frequently Asked Questions about proptest

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

FAQPage Schema

How does property-based testing in Rust find edge cases?▼

Property-based testing in Rust verifies invariants by generating arbitrary data inputs. This approach automatically uncovers edge cases that might cause failures.

How do I write a proptest test using the proptest macro?▼

Write a proptest test by applying the proptest! macro to assert a property holds for arbitrary inputs. This verifies invariants across custom types and collections.

Can I generate arbitrary data for custom Rust types with proptest?▼

Yes, you can generate arbitrary data for custom Rust types using proptest. The optional proptest-derive crate allows deriving Arbitrary for complex nested structures.

How does shrinking reduce failing test cases in Rust?▼

Shrinking in Rust automatically reduces failing arbitrary data inputs to minimal counterexamples. This makes debugging property-based test failures significantly easier.

Do I need the proptest-derive crate to use property-based testing?▼

No, the proptest-derive crate is optional. You can perform property-based testing using the core proptest crate with strategies for collections and custom types.