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use futures::executor::block_on;
use futures::pin_mut;
use futures::stream::{self, Peekable, StreamExt};
#[test]
fn peekable() {
block_on(async {
let peekable: Peekable<_> = stream::iter(vec![1u8, 2, 3]).peekable();
pin_mut!(peekable);
assert_eq!(peekable.as_mut().peek().await, Some(&1u8));
assert_eq!(peekable.collect::<Vec<u8>>().await, vec![1, 2, 3]);
let s = stream::once(async { 1 }).peekable();
pin_mut!(s);
assert_eq!(s.as_mut().peek().await, Some(&1u8));
assert_eq!(s.collect::<Vec<u8>>().await, vec![1]);
});
}
#[test]
fn peekable_mut() {
block_on(async {
let s = stream::iter(vec![1u8, 2, 3]).peekable();
pin_mut!(s);
if let Some(p) = s.as_mut().peek_mut().await {
if *p == 1 {
*p = 5;
}
}
assert_eq!(s.collect::<Vec<_>>().await, vec![5, 2, 3]);
});
}
#[test]
fn peekable_next_if_eq() {
block_on(async {
// first, try on references
let s = stream::iter(vec!["Heart", "of", "Gold"]).peekable();
pin_mut!(s);
// try before `peek()`
assert_eq!(s.as_mut().next_if_eq(&"trillian").await, None);
assert_eq!(s.as_mut().next_if_eq(&"Heart").await, Some("Heart"));
// try after peek()
assert_eq!(s.as_mut().peek().await, Some(&"of"));
assert_eq!(s.as_mut().next_if_eq(&"of").await, Some("of"));
assert_eq!(s.as_mut().next_if_eq(&"zaphod").await, None);
// make sure `next()` still behaves
assert_eq!(s.next().await, Some("Gold"));
// make sure comparison works for owned values
let s = stream::iter(vec![String::from("Ludicrous"), "speed".into()]).peekable();
pin_mut!(s);
// make sure basic functionality works
assert_eq!(s.as_mut().next_if_eq("Ludicrous").await, Some("Ludicrous".into()));
assert_eq!(s.as_mut().next_if_eq("speed").await, Some("speed".into()));
assert_eq!(s.as_mut().next_if_eq("").await, None);
});
}
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