better unit test

crates/wasi-common/src/sched.rs

@@ -5,7 +5,9 @@ use cap_std::time::Instant;
 pub mod subscription;
 pub use cap_std::time::Duration;
 
-use subscription::{MonotonicClockSubscription, RwSubscription, Subscription, SubscriptionResult};
+pub use subscription::{
+    MonotonicClockSubscription, RwEventFlags, RwSubscription, Subscription, SubscriptionResult,
+};
 
 #[wiggle::async_trait]
 pub trait WasiSched {

crates/wasi-common/tokio/tests/poll_oneoff.rs

@@ -1,14 +1,13 @@
 use anyhow::{Context, Error};
-use std::ops::Deref;
 use wasi_common::{
     file::{FdFlags, OFlags},
-    sched::{Poll, Userdata},
-    WasiDir, WasiFile,
+    sched::{Poll, RwEventFlags, SubscriptionResult, Userdata},
+    WasiDir,
 };
-use wasi_tokio::{sched::poll_oneoff, Dir, File};
+use wasi_tokio::{sched::poll_oneoff, Dir};
 
 #[tokio::test(flavor = "multi_thread")]
-async fn main() -> Result<(), Error> {
+async fn empty_file_readable() -> Result<(), Error> {
     let workspace = unsafe { cap_tempfile::tempdir().expect("create tempdir") };
     workspace.create_dir("d").context("create dir")?;
     let d = workspace.open_dir("d").context("open dir")?;
@@ -21,7 +20,48 @@ async fn main() -> Result<(), Error> {
 
     let mut poll = Poll::new();
     poll.subscribe_read(&mut *readable_f, Userdata::from(123));
-    let poll_events = poll_oneoff(&mut poll).await?;
+    poll_oneoff(&mut poll).await?;
+
+    let events = poll.results();
+
+    assert_eq!(events.len(), 1);
+    match events[0] {
+        (SubscriptionResult::Read(Ok((0, flags))), ud) => {
+            assert_eq!(flags, RwEventFlags::empty());
+            assert_eq!(ud, Userdata::from(123));
+        }
+        _ => panic!(""),
+    }
+
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread")]
+async fn empty_file_writable() -> Result<(), Error> {
+    let workspace = unsafe { cap_tempfile::tempdir().expect("create tempdir") };
+    workspace.create_dir("d").context("create dir")?;
+    let d = workspace.open_dir("d").context("open dir")?;
+    let d = Dir::from_cap_std(d);
+
+    let mut writable_f = d
+        .open_file(false, "f", OFlags::CREATE, true, true, FdFlags::empty())
+        .await
+        .context("create writable file")?;
+
+    let mut poll = Poll::new();
+    poll.subscribe_write(&mut *writable_f, Userdata::from(123));
+    poll_oneoff(&mut poll).await?;
+
+    let events = poll.results();
+
+    assert_eq!(events.len(), 1);
+    match events[0] {
+        (SubscriptionResult::Write(Ok((0, flags))), ud) => {
+            assert_eq!(flags, RwEventFlags::empty());
+            assert_eq!(ud, Userdata::from(123));
+        }
+        _ => panic!(""),
+    }
 
     Ok(())
 }