coverage: Add a test for `async` blocks

We have coverage tests that use async functions, but none that use async
blocks.

1 files changed, 37 insertions, 0 deletions

diff --git a/tests/coverage/async_block.coverage b/tests/coverage/async_block.coverage
new file mode 100644
index 00000000000..297397ca26c
--- /dev/null
+++ b/tests/coverage/async_block.coverage
@@ -0,0 +1,37 @@
+   LL|       |#![feature(coverage_attribute)]
+   LL|       |#![feature(noop_waker)]
+   LL|       |// edition: 2021
+   LL|       |
+   LL|      1|fn main() {
+   LL|     17|    for i in 0..16 {
+                      ^16
+   LL|     16|        let future = async {
+   LL|     16|            if i >= 12 {
+   LL|      4|                println!("big");
+   LL|     12|            } else {
+   LL|     12|                println!("small");
+   LL|     12|            }
+   LL|     16|        };
+   LL|     16|        executor::block_on(future);
+   LL|     16|    }
+   LL|      1|}
+   LL|       |
+   LL|       |mod executor {
+   LL|       |    use core::future::Future;
+   LL|       |    use core::pin::pin;
+   LL|       |    use core::task::{Context, Poll, Waker};
+   LL|       |
+   LL|       |    #[coverage(off)]
+   LL|       |    pub fn block_on<F: Future>(mut future: F) -> F::Output {
+   LL|       |        let mut future = pin!(future);
+   LL|       |        let waker = Waker::noop();
+   LL|       |        let mut context = Context::from_waker(&waker);
+   LL|       |
+   LL|       |        loop {
+   LL|       |            if let Poll::Ready(val) = future.as_mut().poll(&mut context) {
+   LL|       |                break val;
+   LL|       |            }
+   LL|       |        }
+   LL|       |    }
+   LL|       |}
+