Attribute Macro run

#[run]

Define an async function that should run to completion on N threads.

Number of threads is configured by #[fuchsia_async::run(N)], and can also take an optional test argument.

Tests written using this macro can be run repeatedly. The environment variable FASYNC_TEST_REPEAT_COUNT sets the number of repetitions each test will be run for, while the environment variable FASYNC_TEST_MAX_CONCURRENCY bounds the maximum concurrent invocations of each test. If FASYNC_TEST_MAX_CONCURRENCY is set to 0 (the default) no bounds to concurrency are applied. If FASYNC_TEST_TIMEOUT_SECONDS is set, it specifies the maximum duration for one repetition of a test. When running tests concurrently the thread pool size will be scaled up by the expected maximum concurrent test executions (to save wall time) - this pool size can be capped with FASYNC_TEST_MAX_THREADS.

#[fuchsia_async::run(4, test)]
async fn test_foo() {}

The test can optionally take a usize argument which specifies which repetition of the test is being performed:

#[fuchsia_async::run(4, test)]
async fn test_foo(test_run: usize) {
  println!("Test repetition #{}", test_run);
}