Macro tokio_test::assert_elapsed

macro_rules! assert_elapsed {
    ($start:expr, $dur:expr) => { ... };
}

Asserts that an exact duration has elapsed since the start instant ±1ms.

use tokio::time::{self, Instant};
use std::time::Duration;
use tokio_test::assert_elapsed;

let start = Instant::now();
let dur = Duration::from_millis(50);
time::sleep(dur).await;
assert_elapsed!(start, dur);

This 1ms buffer is required because Tokio’s hashed-wheel timer has finite time resolution and will not always sleep for the exact interval.