Dicetest

If you want to write a test with randomly generated test data you can use the test builder Dicetest which has the following features:

• It can be configured via source code or environment variables.
• It runs your test repeatedly with different seeds.
• It logs useful information that helps you to debug your test.

You can use Dicetest as part of normal unit tests:

#![allow(unused)]
fn main() {
use dicetest::prelude::*;

#[test]
fn test_foo() {
    // Runs your test with default configuration.
    Dicetest::repeatedly().run(|fate| {
        // Write your test here.
    });
}

#[test]
fn test_bar() {
    // Runs your test with custom configuration.
    Dicetest::repeatedly().passes(10000).run(|fate| {
        // Write your test here.
    });
}
}

The closure contains your test. With the passed fate you can generate test data and make assertions. If the closure panics, Dicetest catches the panic, logs the test result to stdout and resumes the panic.

The logged test result shows a run code. It identifies the counterexample that has panicked. You can rerun the counterexample by setting an environment variable:

DICETEST_DEBUG=3lTBtDxQx6SneW3r4sNLUVoYAREJ8OuO9B0yp31nna0NdwFGFvA4no cargo test

Or you can modify the test:

Dicetest::debug("3lTBtDxQx6SneW3r4sNLUVoYAREJ8OuO9B0yp31nna0NdwFGFvA4no").run(|mut fate| {
    // ...
})

After fixing the bug you can keep the counterexample as a regression test:

Dicetest::repeatedly()
    .regression("3lTBtDxQx6SneW3r4sNLUVoYAREJ8OuO9B0yp31nna0NdwFGFvA4no")
    .run(|mut fate| {
        // ...
    })