time: stream throttle (#1949)

tokio/tests/time_throttle.rs

@@ -0,0 +1,30 @@
+#![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+
+use tokio::time::{self, throttle};
+use tokio_test::*;
+
+use std::time::Duration;
+
+#[tokio::test]
+async fn usage() {
+    time::pause();
+
+    let mut stream = task::spawn(throttle(
+        Duration::from_millis(100),
+        futures::stream::repeat(()),
+    ));
+
+    assert_ready!(stream.poll_next());
+    assert_pending!(stream.poll_next());
+
+    time::advance(Duration::from_millis(90)).await;
+
+    assert_pending!(stream.poll_next());
+
+    time::advance(Duration::from_millis(101)).await;
+
+    assert!(stream.is_woken());
+
+    assert_ready!(stream.poll_next());
+}