test_executors

This crate provides extremely simple, yet useful, async executors. They are primarily useful for writing unit tests without bringing in a full-blown executor such as tokio.

Quick Start

use test_executors::{spin_on, sleep_on};

// Run a simple async function
let result = spin_on(async {
    42
});
assert_eq!(result, 42);

// Run an async function that sleeps
let result = sleep_on(async {
    // Your async code here
    "Hello, async!"
});
assert_eq!(result, "Hello, async!");

Available Executors

The crate provides three main executors:

• spin_on - Polls a future in a busy loop on the current thread. Best for CPU-bound tasks or when latency is critical.
• sleep_on - Polls a future on the current thread, sleeping between polls. Best for I/O-bound tasks to avoid burning CPU.
• spawn_on - Spawns a future on a new thread, polling it there. Best for fire-and-forget tasks.

Platform Support

Native Platforms

All executors work as described above on native platforms (Linux, macOS, Windows, etc.).

WebAssembly Support

This crate has special support for wasm32 targets:

• The async_test macro automatically adapts to use wasm-bindgen-test on WASM
• spawn_local uses wasm_bindgen_futures::spawn_local on WASM targets

Features

async_test Macro

The async_test macro allows you to write async tests that work on both native and WASM targets:

use test_executors::async_test;

#[async_test]
async fn my_test() {
    let value = async { 42 }.await;
    assert_eq!(value, 42);
}

Integration with some_executor

This crate implements the some_executor trait for all executors, allowing them to be used in executor-agnostic code:

use test_executors::aruntime::SpinRuntime;
use some_executor::SomeExecutor;

let mut runtime = SpinRuntime::new();
// Use runtime with some_executor traits

Utilities

The crate also provides utility functions and types:

• poll_once and poll_once_pin - Poll a future exactly once
• spawn_local - Platform-aware spawning that works on both native and WASM

Documentation

For detailed API documentation including all function signatures, examples, and implementation details, see the docs.rs documentation.

License

Licensed under either of:

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.