#[path = "../../../os-virtio-backpressure/src/lib.rs"]
mod virtio_backpressure;

use virtio_backpressure::{Budget, Error};

#[test]
fn os_virtqueue_backpressure_limit_and_retry() {
    let mut budget = Budget::<8>::new(8).unwrap();
    let first = budget.claim(0, 3).unwrap();
    let second = budget.claim(3, 3).unwrap();
    let before = budget.snapshot();
    assert_eq!(budget.claim(6, 3), Err(Error::Again));
    assert_eq!(budget.snapshot(), before);
    assert_eq!(budget.complete(0), Ok(first));
    let retried = budget.claim(6, 3).unwrap();
    assert_eq!(retried.descriptors, 3);
    assert_eq!(budget.complete(3), Ok(second));
    assert_eq!(budget.complete(6), Ok(retried));
    assert_eq!(budget.snapshot().used_descriptors, 0);
}

#[test]
fn os_virtqueue_backpressure_reject_and_reset() {
    assert!(matches!(Budget::<8>::new(3), Err(Error::InvalidQueue)));
    let mut budget = Budget::<8>::new(8).unwrap();
    let all = budget.claim(0, 8).unwrap();
    let before = budget.snapshot();
    assert_eq!(budget.claim(1, 1), Err(Error::Again));
    assert_eq!(budget.claim(0, 1), Err(Error::DuplicateHead));
    assert_eq!(budget.complete(7), Err(Error::UnknownHead));
    assert_eq!(budget.observe_reset(1, 0), Err(Error::NotReset));
    assert_eq!(budget.snapshot(), before);
    assert_eq!(budget.complete(0), Ok(all));
    assert_eq!(budget.complete(0), Err(Error::UnknownHead));
    budget.claim(1, 1).unwrap();
    budget.observe_reset(0, 0).unwrap();
    assert_eq!(budget.snapshot().used_descriptors, 0);
}