Global onError doesn't called for FakeApplication (tests)

Reproduced on Play 2.2.2

1. Catch all errors and handle them in Global.scala

   import play.api._
   import play.api.mvc.{Results, WithFilters}
   import scala.concurrent.Future
   
   object Global extends GlobalSettings {
       override def onError(request : play.api.mvc.RequestHeader, ex : Throwable) : scala.concurrent.Future[play.api.mvc.SimpleResult] = {
               Future.successful(Results.BadRequest)
       }
   }
   

2. Generate exception in action

   package controllers
   
   import play.api._
   import play.api.mvc._
   
   object Application extends Controller {
     def index = Action {
       throw new RuntimeException("Unexpected")
       Ok
     }
   }
   

3. The problem is that if you call that action in browser, you’ll get 400 BAD_REQUEST exactly like it’s handled in Global.scala, but you can’t cover it with test because this test fails with exception:

   @RunWith(classOf[JUnitRunner]) class ApplicationSpec extends Specification { “Application” should { “render the index page” in new WithApplication{ val home = route(FakeRequest(GET, “/”)).get status(home) must equalTo(BAD_REQUEST) } } }

[scadgek]

Hi @jroper,

Just wanted to inquire whether you haven’t changed your position after 3 years. I can find a few counterarguments to your claim that we don’t need to test onError()'s behaviour when testing controllers. In my view, when I test a controller, what I want to accomplish is to emulate someone issuing an HTTP request to my service and test the result he receives, which is in this case the result on onError()'s execution. At the same time, if I want to test that the proper exception is thrown, I’ll test the underlying controller’s class, and this will also encourage decoupling of business logic from the router’s logic.

Of course, the approach you suggested - writing tests for the HttpErrorHandler itself - would also work, but I believe this makes testing the controller either redundant or incomplete, since it does nothing besides parsing request and by itself does not throw any exceptions - instead it returns Result instances.

Please tell us what you think of this, and thanks in advance!

[zarinfam]

Java 8 version of routeWithOnError for play 2.4+:

public static Result routeWithOnError(Http.RequestBuilder requestBuilder) throws InterruptedException, ExecutionException, TimeoutException {
    CompletableFuture<Result> future = CompletableFuture.supplyAsync(() -> route(requestBuilder));

    BiFunction<Result, Throwable, CompletionStage<Result>> f =
            (r, t) -> (t == null)
                    ? CompletableFuture.supplyAsync(() -> r)
                    : new CustomHttpErrorHandler().onError(null, t);

    return future.handleAsync(f).thenCompose(x -> x).get(20000, TimeUnit.MILLISECONDS);
}