add tests to api

api/src/test/mock_stream_sink.rs

@@ -0,0 +1,82 @@
+use futures_util::sink::{unfold, Unfold};
+use futures_util::{Sink, SinkExt, Stream};
+use std::fmt::Display;
+use std::future::Future;
+use std::pin::Pin;
+use std::sync::Arc;
+use std::task::{Context, Poll};
+use tokio::sync::mpsc;
+use tokio::sync::mpsc::error::SendError;
+use tokio::sync::mpsc::{Receiver, Sender};
+
+pub struct MockStreamSinkControl<T, R> {
+    pub incoming: Sender<T>,
+    pub outgoing: Receiver<R>,
+}
+
+pub struct MockStreamSink<T, U1, U2> {
+    stream_rx: Receiver<T>,
+    sink_tx: Pin<Box<Unfold<u32, U1, U2>>>,
+}
+
+impl<T, U1, U2> Stream for MockStreamSink<T, U1, U2>
+where
+    Self: Unpin,
+{
+    type Item = T;
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        self.stream_rx.poll_recv(cx)
+    }
+}
+
+impl<T, R, U1, U2, E> Sink<R> for MockStreamSink<T, U1, U2>
+where
+    U1: FnMut(u32, R) -> U2,
+    U2: Future<Output = Result<u32, E>>,
+{
+    type Error = E;
+
+    fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+        self.sink_tx.poll_ready_unpin(cx)
+    }
+
+    fn start_send(mut self: Pin<&mut Self>, item: R) -> Result<(), Self::Error> {
+        self.sink_tx.start_send_unpin(item)
+    }
+
+    fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+        self.sink_tx.poll_flush_unpin(cx)
+    }
+
+    fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+        self.sink_tx.poll_close_unpin(cx)
+    }
+}
+
+pub fn create_mock_stream_sink<T: Send, R: Send + 'static>() -> (
+    MockStreamSinkControl<T, R>,
+    impl Stream<Item = T> + Sink<R, Error = impl Display>,
+) {
+    let (stream_tx, stream_rx) = mpsc::channel::<T>(1);
+    let (sink_tx, sink_rx) = mpsc::channel::<R>(1);
+
+    let sink_tx = Arc::new(sink_tx);
+
+    (
+        MockStreamSinkControl {
+            incoming: stream_tx,
+            outgoing: sink_rx,
+        },
+        MockStreamSink::<T, _, _> {
+            stream_rx,
+            sink_tx: Box::pin(unfold(0u32, move |_, item| {
+                let sink_tx = sink_tx.clone();
+                async move {
+                    sink_tx.send(item).await?;
+                    Ok(0u32) as Result<_, SendError<R>>
+                }
+            })),
+        },
+    )
+}