How to use proptest crate in Rust property testing

Add proptest as a dev-dependency in Cargo.toml, then use #[test] functions with proptest! macros to define strategies and assertions.

[dev-dependencies]
proptest = { version = "0.10", default-features = false, features = ["alloc"] }

use proptest::prelude::*;

#[test]
fn test_addition() {
    proptest!(|(a in any::<i32>(), b in any::<i32>())| {
        prop_assert_eq!(a + b, b + a);
    });
}

Set PROPTEST_CASES in your environment to control test iterations, as shown in CI configurations.

Proptest is a tool that automatically generates random data to test your code instead of you writing specific test cases. It helps find hidden bugs by checking if your functions work correctly for thousands of different inputs, not just the ones you thought of. Think of it as a tireless robot tester that tries to break your code by feeding it weird numbers and edge cases.