Struct TestAsyncExecutor 

pub struct TestAsyncExecutor { /* private fields */ }

Single-threaded Future task executor for testing purposes.

Enqueue top-level Futures via spawn() and poll all currently enqueued ones to completion via run_to_completion().

Enqueued Futures may enqueue further ones from their Future::poll() and poll on the resulting TestAsyncExecutorTaskWaiter.

Implementations

impl TestAsyncExecutor

pub fn new() -> GenericArc<Self>

Create a new TestAsyncExecutor instance.

pub fn spawn<F: Future + Send + 'static>( this: &GenericArc<Self>, f: F, ) -> TestAsyncExecutorTaskWaiter<F::Output>

where F::Output: Send + 'static,

Enqueue a top-level Future for polling from a subsequent run_to_completion() invocation.

See also:

• TestAsyncExecutorTaskWaiter
• run_to_completion()

pub fn run_to_completion(this: &GenericArc<Self>)

Poll all currently enqueued Futures to completion.

A Future is in “runnable” state right after it has been enqueued and ceases to once its Future::poll() returns a status of Pending. A non-runnable Future becomes runnable again when woken. There must always be at least one runnable Future left, or the executor will become stuck and report the fact via a panic.

run_to_completion() polls the runnable enqueued Future in a round-robin fashion, in the order of their enqueueing. That is, if futures [a, b, c] are enqueued, with a non-runnable and b and c runnable, and the cursor is at a or b, then b will get polled first, followed by c, followed by a if that became runnable in the course of polling b or c.