ExceptionHandler doesn't work with spray test-kit? - scala

Question

I'm trying Spray's ExceptionHandler using an example in this guide: http://spray.io/documentation/1.2.2/spray-routing/key-concepts/exception-handling/
class MyServiceActor extends Actor with MyService {
def actorRefFactory = context
def receive = runRoute(handleExceptions(myExceptionHandler)(myRoute))
implicit def myExceptionHandler(implicit log: LoggingContext) =
ExceptionHandler {
case e: ArithmeticException =>
requestUri { uri =>
complete(InternalServerError, "Bad numbers, bad result!!!")
}
}
}
I intentionally throw ArithmeticException in the route like this:
trait MyService extends HttpService {
val myRoute =
path("") {
get {
complete {
throw new ArithmeticException("Oops, I failed!")
"Hello World"
}
}
}
}
If I made a request with curl, it returns the error message Bad numbers, bad result!!! correctly. However when testing with Specs2 + spray testkit, it never returns the correct error message, instead it returns default 500 code error message There was an internal server error. Even using sealRoute doesn't help.
"Test" in {
Get() ~> sealRoute(myRoute) ~> check {
println(responseAs[String]) // Always print `There was an internal server error.`
ok
}
}
And on the console, I would see error trace:
[ERROR] [07/07/2016 00:31:24.661] [specs2.DefaultExecutionStrategy-1] [ActorSystem(com-example-MyServiceSpec)] Error during processing of request HttpRequest(GET,http://example.com/,List(),Empty,HTTP/1.1)
java.lang.ArithmeticException: Oops, I failed!
at com.example.MyService$$anonfun$1.apply(MyService.scala:62)
at com.example.MyService$$anonfun$1.apply(MyService.scala:61)
at spray.routing.directives.RouteDirectives$$anonfun$complete$1$$anon$3.apply(RouteDirectives.scala:49)
at spray.routing.directives.RouteDirectives$$anonfun$complete$1$$anon$3.apply(RouteDirectives.scala:48)
at spray.routing.directives.BasicDirectives$$anonfun$mapRequestContext$1$$anonfun$apply$1.apply(BasicDirectives.scala:30)
...
I put a println command in the myExceptionHandler and found out the myExceptionHandler never get executed.
Anyone know why it doesn't work and the solution?

Answer 1

Apparently sealRoute is not enough, because the exception handler is resolved implicitly, as described here: http://spray.io/documentation/1.2.4/spray-testkit/
In your case, MyServiceActor has an exception handler, but in the test case you use MyService/myRoute directly, so the exception handler is not picked up.
This documentation page was useful: http://spray.io/documentation/1.2.4/spray-routing/key-concepts/exception-handling/
The solution is to bring an implicit ExceptionHandler into scope in the test case. So in this example:
"Test" in {
implicit val testExceptionHandler = ExceptionHandler {
case e: ArithmeticException =>
requestUri { uri =>
complete(InternalServerError, "Bad numbers, bad result!!!")
}
}
Get() ~> sealRoute(myRoute) ~> check {
println(responseAs[String])
ok
}
}
It worked, but of course the duplication is not super elegant. Maybe you can access the exception handler from MyServiceActor in your test and reuse production code. I just put testExceptionHandler into a base class all tests inherit from.