content: /*
   * Copyright (C) 2009-2025 Lightbend Inc. <https://www.lightbend.com>
   */
  
  package akka.stream.javadsl;
  
  import static org.junit.Assert.assertEquals;
  
  import akka.NotUsed;
  import akka.japi.Pair;
  import akka.stream.StreamTest;
  import akka.testkit.AkkaJUnitActorSystemResource;
  import akka.testkit.AkkaSpec;
  import java.util.Arrays;
  import java.util.List;
  import java.util.concurrent.CompletableFuture;
  import java.util.concurrent.CompletionStage;
  import java.util.concurrent.TimeUnit;
  import org.junit.ClassRule;
  import org.junit.Test;
  import scala.concurrent.Future;
  
  public class LazyAndFutureSourcesTest extends StreamTest {
  
    @ClassRule
    public static AkkaJUnitActorSystemResource actorSystemResource =
        new AkkaJUnitActorSystemResource("LazyAndFutureSourcesTest", AkkaSpec.testConf());
  
    public LazyAndFutureSourcesTest() {
      super(actorSystemResource);
    }
  
    // note these are minimal happy path tests to cover API, more thorough tests are on the Scala side
  
    @Test
    public void future() throws Exception {
      CompletionStage<List<String>> result =
          Source.future(Future.successful("one")).runWith(Sink.seq(), system);
  
      assertEquals(Arrays.asList("one"), result.toCompletableFuture().get(3, TimeUnit.SECONDS));
    }
  
    @Test
    public void completionStage() throws Exception {
      CompletionStage<String> one = CompletableFuture.completedFuture("one");
      CompletionStage<List<String>> result = Source.completionStage(one).runWith(Sink.seq(), system);
  
      assertEquals(Arrays.asList("one"), result.toCompletableFuture().get(3, TimeUnit.SECONDS));
    }
  
    @Test
    public void completionStageSource() throws Exception {
      Pair<CompletionStage<NotUsed>, CompletionStage<List<String>>> result =
          Source.completionStageSource(CompletableFuture.completedFuture(Source.single("one")))
              .toMat(Sink.seq(), Keep.both())
              .run(system);
  
      CompletionStage<NotUsed> nestedMatVal = result.first();
      CompletionStage<List<String>> list = result.second();
      assertEquals(Arrays.asList("one"), list.toCompletableFuture().get(3, TimeUnit.SECONDS));
      // Future adaption to completionstage of matval means we cannot count on matval future being
      // completed just because stream is
      nestedMatVal.toCompletableFuture().get(3, TimeUnit.SECONDS);
    }
  
    @Test
    public void lazySingle() throws Exception {
      CompletionStage<List<String>> list = Source.lazySingle(() -> "one").runWith(Sink.seq(), system);
  
      assertEquals(Arrays.asList("one"), list.toCompletableFuture().get(3, TimeUnit.SECONDS));
    }
  
    @Test
    public void lazyCompletionStage() throws Exception {
      CompletionStage<List<String>> list =
          Source.lazyCompletionStage(() -> CompletableFuture.completedFuture("one"))
              .runWith(Sink.seq(), system);
  
      assertEquals(Arrays.asList("one"), list.toCompletableFuture().get(3, TimeUnit.SECONDS));
    }
  
    @Test
    public void lazySource() throws Exception {
      Pair<CompletionStage<NotUsed>, CompletionStage<List<String>>> result =
          Source.lazySource(() -> Source.single("one")).toMat(Sink.seq(), Keep.both()).run(system);
  
      CompletionStage<NotUsed> nestedMatVal = result.first();
      CompletionStage<List<String>> list = result.second();
      assertEquals(Arrays.asList("one"), list.toCompletableFuture().get(3, TimeUnit.SECONDS));
      // Future adaption to completionstage of matval means we cannot count on matval future being
      // completed just because stream is
      nestedMatVal.toCompletableFuture().get(3, TimeUnit.SECONDS);
    }
  
    @Test
    public void lazyCompletionStageSource() throws Exception {
      Pair<CompletionStage<NotUsed>, CompletionStage<List<String>>> result =
          Source.lazyCompletionStageSource(
                  () -> CompletableFuture.completedFuture(Source.single("one")))
              .toMat(Sink.seq(), Keep.both())
              .run(system);
  
      CompletionStage<NotUsed> nestedMatVal = result.first();
      CompletionStage<List<String>> list = result.second();
      assertEquals(Arrays.asList("one"), list.toCompletableFuture().get(3, TimeUnit.SECONDS));
      // flatMap/thenCompose of matval means we cannot count on matval future being completed just
      // because stream is
      nestedMatVal.toCompletableFuture().get(3, TimeUnit.SECONDS);
    }
  }
  