1use futures::executor::block_on_stream;
2use futures::future::{err, ok, TryFutureExt};
3use futures::sink::Sink;
4use futures::stream::Stream;
5use futures::stream::{self, StreamExt};
6use futures::task::{Context, Poll};
7use std::marker::PhantomData;
8use std::pin::Pin;
9
10#[test]
11fn successful_future() {
12 let stream_items = vec![17, 19];
13 let future_of_a_stream = ok::<_, bool>(stream::iter(stream_items).map(Ok));
14
15 let stream = future_of_a_stream.try_flatten_stream();
16
17 let mut iter = block_on_stream(stream);
18 assert_eq!(Ok(17), iter.next().unwrap());
19 assert_eq!(Ok(19), iter.next().unwrap());
20 assert_eq!(None, iter.next());
21}
22
23#[test]
24fn failed_future() {
25 struct PanickingStream<T, E> {
26 _marker: PhantomData<(T, E)>,
27 }
28
29 impl<T, E> Stream for PanickingStream<T, E> {
30 type Item = Result<T, E>;
31
32 fn poll_next(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Option<Self::Item>> {
33 panic!()
34 }
35 }
36
37 let future_of_a_stream = err::<PanickingStream<bool, u32>, _>(10);
38 let stream = future_of_a_stream.try_flatten_stream();
39 let mut iter = block_on_stream(stream);
40 assert_eq!(Err(10), iter.next().unwrap());
41 assert_eq!(None, iter.next());
42}
43
44#[test]
45fn assert_impls() {
46 struct StreamSink<T, E, Item>(PhantomData<(T, E, Item)>);
47
48 impl<T, E, Item> Stream for StreamSink<T, E, Item> {
49 type Item = Result<T, E>;
50 fn poll_next(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Option<Self::Item>> {
51 panic!()
52 }
53 }
54
55 impl<T, E, Item> Sink<Item> for StreamSink<T, E, Item> {
56 type Error = E;
57 fn poll_ready(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
58 panic!()
59 }
60 fn start_send(self: Pin<&mut Self>, _: Item) -> Result<(), Self::Error> {
61 panic!()
62 }
63 fn poll_flush(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
64 panic!()
65 }
66 fn poll_close(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
67 panic!()
68 }
69 }
70
71 fn assert_stream<S: Stream>(_: &S) {}
72 fn assert_sink<S: Sink<Item>, Item>(_: &S) {}
73 fn assert_stream_sink<S: Stream + Sink<Item>, Item>(_: &S) {}
74
75 let s = ok(StreamSink::<(), (), ()>(PhantomData)).try_flatten_stream();
76 assert_stream(&s);
77 assert_sink(&s);
78 assert_stream_sink(&s);
79 let s = ok(StreamSink::<(), (), ()>(PhantomData)).flatten_sink();
80 assert_stream(&s);
81 assert_sink(&s);
82 assert_stream_sink(&s);
83}
84