akka-http-completeWithOptional.java

import akka.http.javadsl.marshallers.jackson.Jackson;
import akka.http.javadsl.model.HttpRequest;
import akka.http.javadsl.model.StatusCodes;
import akka.http.javadsl.server.Route;
import akka.http.javadsl.testkit.JUnitRouteTest;
import org.junit.Test;

import java.util.Optional;

public class RejectEmptyResponseBug extends JUnitRouteTest {

  @Test
  public void testRejectEmptyResponseBug() {

    final Route route = path("foo", () -> completeOK(Optional.empty(), Jackson.marshaller()));
    final Route route2 = rejectEmptyResponse(() -> path("foo", () -> completeOK(Optional.empty(), Jackson.marshaller())));
    final Route route3 = path("foo", () -> completeOK(Optional.of(42), Jackson.marshaller()));

    //what happens
    testRoute(route).run(HttpRequest.GET("/foo")).assertEntity("{\"present\":false}");
    testRoute(route2).run(HttpRequest.GET("/foo")).assertEntity("{\"present\":false}");
    testRoute(route3).run(HttpRequest.GET("/foo")).assertEntity("{\"present\":true}");

    //what is expected
    testRoute(route).run(HttpRequest.GET("/foo")).assertEntity("");
    testRoute(route2).run(HttpRequest.GET("/foo")).assertStatusCode(StatusCodes.NOT_FOUND);
    testRoute(route3).run(HttpRequest.GET("/foo")).assertEntity("42");

  }
}