test: Add stream::delay test code

Author: k-nasa

src/stream/stream/mod.rs

@@ -587,16 +587,12 @@ extension_trait! {
  use async_std::stream;
  use std::time::Duration;
 
- let a = stream::once(1).delay(Duration::from_millis(200));
- let b = stream::once(2).delay(Duration::from_millis(100));
- let c = stream::once(3).delay(Duration::from_millis(300));
+ let mut s = stream::from_iter(vec![0u8, 1, 2]).delay(Duration::from_millis(200));
 
- let s = stream::join!(a, b, c);
-
- assert_eq!(stream.next().await, Some(1));
- assert_eq!(stream.next().await, Some(2));
- assert_eq!(stream.next().await, Some(3));
- assert_eq!(stream.next().await, None);
+ assert_eq!(s.next().await, Some(0));
+ assert_eq!(s.next().await, Some(1));
+ assert_eq!(s.next().await, Some(2));
+ assert_eq!(s.next().await, None);
  #
  # }) }
  ```