I wrote a library for property based testing in rust. I’ll post part of the readme here for ease

Property-Based Testing for Rust - An ergonomic, powerful, and feature-rich property testing library with minimal boilerplate.

Features

🚀 Ergonomic API - Test properties with closures, no boilerplate

🎯 Automatic Generator Inference - Smart type-based generator selection

🔧 Derive Macros - #[derive(Generator)] for custom types

📦 Declarative Macros - property!, assert_property!, generator!

⚡ Async Support - First-class async property testing

🔄 Smart Shrinking - Automatic minimal counterexample finding

💾 Failure Persistence - Save and replay failing test cases (optional)

🔧 CLI Tool - Manage failures from the command line (protest-cli)

🎨 Fluent Builders - Chain configuration methods naturally

🧪 Common Patterns - Built-in helpers for mathematical properties

🔀 Parallel Execution - Run tests in parallel for speed

📊 Statistics & Coverage - Track generation and test coverage

🎭 Flexible - Works with any type, sync or async

Ultra-Simple Example

use protest::*;

#[test]
fn test_addition_commutative() {
// Test that addition is commutative with just one line!
property!(generator!(i32, -100, 100), |(a, b)| a + b == b + a);
}

Ergonomic API Example

use protest::ergonomic::*;

#[test]
fn test_reverse_twice_is_identity() {
property(|mut v: Vec<i32>| {
let original = v.clone();
v.reverse();
v.reverse();
v == original
})
.iterations(1000)
.run_with(VecGenerator::new(IntGenerator::new(-50, 50), 0, 100))
.expect("Property should hold");
}

Attribute Macro Example

use protest::property_test;

#[property_test(iterations = 100)]
fn test_string_length(s: String) {
// Generator automatically inferred from type
assert!(s.len() >= 0);
}

Custom Struct Example

use protest::Generator;

#[derive(Debug, Clone, PartialEq, Generator)]
struct User {
#[generator(range = "1..1000")]
id: u32,

#[generator(length = "5..50")]
name: String,

age: u8,
active: bool,
}

#[property_test]
fn test_user_id(user: User) {
assert!(user.id > 0 && user.id < 1000);
}