Macro tokio_test::assert_ready_err

macro_rules! assert_ready_err {
    ($e:expr) => { ... };
    ($e:expr, $($msg:tt),+) => { ... };
}

Assert a Poll<Result<...>> is ready and Err, returning the error.

This will invoke panic! if the provided Poll does not evaluate to Poll::Ready(Err(..)) at runtime.

Custom Messages

This macro has a second form, where a custom panic message can be provided with or without arguments for formatting.

Examples

use std::future::Future;
use futures_util::{future, pin_mut};
use tokio_test::{assert_ready_err, task};

task::mock(|cx| {
    let fut = future::err::<(), _>(());

    pin_mut!(fut);
    assert_ready_err!(fut.poll(cx));
})