Exception

[ERROR] [04/27/2017 13:41:56.845] [pool-6-thread-8-ScalaTest-running-PathDirectivesSpec] [akka.actor.ActorSystemImpl(akka-http-scaladsl-server-directives-PathDirectivesSpec)] Error during processing of request: 'Rejection handler still produced new rejections after 8 iterations. Is there an infinite handler cycle? Initial rejections: List() final rejections: List()'. Completing with 500 Internal Server Error response. To change default exception handling behavior, provide a custom ExceptionHandler.
java.lang.RuntimeException: Rejection handler still produced new rejections after 8 iterations. Is there an infinite handler cycle? Initial rejections: List() final rejections: List()
	at scala.sys.package$.error(package.scala:27)
	at akka.http.scaladsl.server.directives.ExecutionDirectives$$anonfun$handleRejections$1.akka$http$scaladsl$server$directives$ExecutionDirectives$class$$anonfun$$handle$1(ExecutionDirectives.scala:55)
	at akka.http.scaladsl.server.directives.ExecutionDirectives$$anonfun$handleRejections$1$$anonfun$akka$http$scaladsl$server$directives$ExecutionDirectives$class$$anonfun$$handle$1$1.apply(ExecutionDirectives.scala:51)
	at akka.http.scaladsl.server.directives.ExecutionDirectives$$anonfun$handleRejections$1$$anonfun$akka$http$scaladsl$server$directives$ExecutionDirectives$class$$anonfun$$handle$1$1.apply(ExecutionDirectives.scala:51)

ignoreTrailingSlash

def ignoreTrailingSlash: Directive0 = Directive[Unit] { inner ⇒
  import ExecutionDirectives._
  val totallyMissingHandler = RejectionHandler.newBuilder()
    .handleNotFound {
      mapRequestContext(req ⇒ req.withUnmatchedPath(flipTrailingSlash(req.unmatchedPath)))(inner())
    }
    .result()
  
  handleRejections(totallyMissingHandler) {
    inner()
  }
}

/// TESTS

"the `ignoreTrailingSlash` directive" should {
    val route = ignoreTrailingSlash {
      path("foo") { completeOk } ~
        (pathPrefix("bar") & pathEndOrSingleSlash) { completeOk }
    }

    "pass if the request path doesn't have a trailing slash" in {
      Get("/foo") ~> route ~> check { response shouldEqual Ok }
    }

    "pass if the request path has a trailing slash" in {
      Get("/foo/") ~> route ~> check { response shouldEqual Ok }
    }

    "do only 1 pass if path already checks for trailing slash" in {
      Get("/bar/") ~> route ~> check { response shouldEqual Ok }
    }

    "reject if request can't be matched with nor without a trailing slash" in {
      Get("/foz") ~> route ~> check {
        println(response)
        handled shouldEqual false
      }
    }
  }