Cherry-picked additional tests from #2856

core/shared/src/test/scala/fs2/concurrent/ChannelSuite.scala

@@ -30,6 +30,19 @@ import scala.concurrent.duration._
 import org.scalacheck.effect.PropF.forAllF
 
 class ChannelSuite extends Fs2Suite {
+
+  test("receives some simple elements above capacity and closes") {
+    val test = Channel.bounded[IO, Int](5).flatMap { chan =>
+      val senders = 0.until(10).toList.parTraverse_ { i =>
+        IO.sleep(i.millis) *> chan.send(i)
+      }
+
+      senders &> (IO.sleep(15.millis) *> chan.close *> chan.stream.compile.toVector)
+    }
+
+    TestControl.executeEmbed(test)
+  }
+
   test("Channel receives all elements and closes") {
     forAllF { (source: Stream[Pure, Int]) =>
       Channel.unbounded[IO, Int].flatMap { chan =>
@@ -133,7 +146,7 @@ class ChannelSuite extends Fs2Suite {
     p.assertEquals(true)
   }
 
-  test("Channel.synchronous respects fifo") {
+  test("synchronous respects fifo") {
     val l = for {
       chan <- Channel.synchronous[IO, Int]
       _ <- (0 until 5).toList.traverse_ { i =>
@@ -147,7 +160,95 @@ class ChannelSuite extends Fs2Suite {
       result <- IO.sleep(5.seconds) *> chan.stream.compile.toList
     } yield result
 
-    TestControl.executeEmbed(l).assertEquals((0 until 5).toList)
+    TestControl.executeEmbed(l).assertEquals((0 until 5).toList).parReplicateA_(100)
   }
 
+  test("complete all blocked sends after closure") {
+    val test = for {
+      chan <- Channel.bounded[IO, Int](2)
+
+      fiber <- 0.until(5).toList.parTraverse(chan.send(_)).start
+      _ <- IO.sleep(1.second)
+      _ <- chan.close
+
+      results <- chan.stream.compile.toList
+      _ <- IO(assert(results.length == 5))
+      _ <- IO(assert(0.until(5).forall(results.contains(_))))
+
+      sends <- fiber.joinWithNever
+      _ <- IO(assert(sends.forall(_ == Right(()))))
+    } yield ()
+
+    TestControl.executeEmbed(test).parReplicateA_(100)
+  }
+
+  test("eagerly close sendAll upstream") {
+    for {
+      countR <- IO.ref(0)
+      chan <- Channel.unbounded[IO, Unit]
+
+      incrementer = Stream.eval(countR.update(_ + 1)).repeat.take(5)
+      upstream = incrementer ++ Stream.eval(chan.close).drain ++ incrementer
+
+      results <- chan.stream.concurrently(upstream.through(chan.sendAll)).compile.toList
+
+      _ <- IO(assert(results.length == 5))
+      count <- countR.get
+      _ <- IO(assert(count == 6)) // we have to overrun the closure to detect it
+    } yield ()
+  }
+
+  def blackHole(s: Stream[IO, Unit]) =
+    s.repeatPull(_.uncons.flatMap {
+      case None => Pull.pure(None)
+      case Some((hd, tl)) =>
+        val action = IO.delay(0.until(hd.size).foreach(_ => ()))
+        Pull.eval(action).as(Some(tl))
+    })
+
+  @inline
+  private def sendAll(list: List[Unit], action: IO[Unit]) =
+    list.foldLeft(IO.unit)((acc, _) => acc *> action)
+
+  test("sendPull") {
+    val test = Channel.bounded[IO, Unit](8).flatMap { channel =>
+      val action = List.fill(64)(()).traverse_(_ => channel.send(()).void) *> channel.close
+      action.start *> channel.stream.through(blackHole).compile.drain
+    }
+
+    test.replicateA_(if (isJVM) 1000 else 1)
+  }
+
+  test("sendPullPar8") {
+    val lists = List.fill(8)(List.fill(8)(()))
+
+    val test = Channel.bounded[IO, Unit](8).flatMap { channel =>
+      val action = lists.parTraverse_(sendAll(_, channel.send(()).void)) *> channel.close
+
+      action &> channel.stream.through(blackHole).compile.drain
+    }
+
+    test.replicateA_(if (isJVM) 10000 else 1)
+  }
+
+  test("synchronous with many concurrents and close") {
+    val test = Channel.synchronous[IO, Int].flatMap { ch =>
+      0.until(20).toList.parTraverse_(i => ch.send(i).iterateWhile(_.isRight)) &>
+        ch.stream.concurrently(Stream.eval(ch.close.delayBy(1.seconds))).compile.drain
+    }
+
+    test.parReplicateA(100)
+  }
+
+  test("complete closed immediately without draining") {
+    val test = Channel.bounded[IO, Int](20).flatMap { ch =>
+      for {
+        _ <- 0.until(10).toList.parTraverse_(ch.send(_))
+        _ <- ch.close
+        _ <- ch.closed
+      } yield ()
+    }
+
+    TestControl.executeEmbed(test)
+  }
 }