1 use futures::executor::block_on;
2 use futures::pin_mut;
3 use futures::stream::{self, Peekable, StreamExt};
4
5 #[test]
peekable()6 fn peekable() {
7 block_on(async {
8 let peekable: Peekable<_> = stream::iter(vec![1u8, 2, 3]).peekable();
9 pin_mut!(peekable);
10 assert_eq!(peekable.as_mut().peek().await, Some(&1u8));
11 assert_eq!(peekable.collect::<Vec<u8>>().await, vec![1, 2, 3]);
12
13 let s = stream::once(async { 1 }).peekable();
14 pin_mut!(s);
15 assert_eq!(s.as_mut().peek().await, Some(&1u8));
16 assert_eq!(s.collect::<Vec<u8>>().await, vec![1]);
17 });
18 }
19
20 #[test]
peekable_mut()21 fn peekable_mut() {
22 block_on(async {
23 let s = stream::iter(vec![1u8, 2, 3]).peekable();
24 pin_mut!(s);
25 if let Some(p) = s.as_mut().peek_mut().await {
26 if *p == 1 {
27 *p = 5;
28 }
29 }
30 assert_eq!(s.collect::<Vec<_>>().await, vec![5, 2, 3]);
31 });
32 }
33
34 #[test]
peekable_next_if_eq()35 fn peekable_next_if_eq() {
36 block_on(async {
37 // first, try on references
38 let s = stream::iter(vec!["Heart", "of", "Gold"]).peekable();
39 pin_mut!(s);
40 // try before `peek()`
41 assert_eq!(s.as_mut().next_if_eq(&"trillian").await, None);
42 assert_eq!(s.as_mut().next_if_eq(&"Heart").await, Some("Heart"));
43 // try after peek()
44 assert_eq!(s.as_mut().peek().await, Some(&"of"));
45 assert_eq!(s.as_mut().next_if_eq(&"of").await, Some("of"));
46 assert_eq!(s.as_mut().next_if_eq(&"zaphod").await, None);
47 // make sure `next()` still behaves
48 assert_eq!(s.next().await, Some("Gold"));
49
50 // make sure comparison works for owned values
51 let s = stream::iter(vec![String::from("Ludicrous"), "speed".into()]).peekable();
52 pin_mut!(s);
53 // make sure basic functionality works
54 assert_eq!(s.as_mut().next_if_eq("Ludicrous").await, Some("Ludicrous".into()));
55 assert_eq!(s.as_mut().next_if_eq("speed").await, Some("speed".into()));
56 assert_eq!(s.as_mut().next_if_eq("").await, None);
57 });
58 }
59