DurationTestTools

DurationTestTools.scala

import scala.concurrent.duration._

trait DurationTestTools {
    implicit def duration2DurationCompare(duration: Duration): DurationCompare = DurationCompare(duration)

    case class DurationCompare(duration: Duration) {
        def shouldBeMinusThan(expectedDuration: Duration) { assert(duration.compare(expectedDuration) < 0, s"$duration was not minus than $expectedDuration") }
        def shouldBeMinusOrEqualThan(expectedDuration: Duration) { assert(duration.compare(expectedDuration) <= 0, s"$duration was not minus or equal than $expectedDuration") }
        def shouldBeGreaterThan(expectedDuration: Duration) { assert(duration.compare(expectedDuration) > 0, s"$duration was not greater than $expectedDuration") }
        def shouldBeGreaterOrEqualThan(expectedDuration: Duration) { assert(duration.compare(expectedDuration) >= 0, s"$duration was not greater or equal than $expectedDuration") }
        def shouldBeEqualTo(expectedDuration: Duration) { assert(duration.compare(expectedDuration) == 0, s"$duration was not equal to $expectedDuration") }
    }

    def mesureTimeExecutionOf[T](toMesure: => T): (Duration, T) = {
        val start = System.currentTimeMillis()
        val result = toMesure
        val stop = System.currentTimeMillis()

        ((stop - start) milliseconds, result)
    }
}

DurationTestToolsExample.scala

import org.scalatest.{Matchers, BeforeAndAfterAll, FunSuite}
import scala.concurrent.duration._

class ServerTest extends FunSuite with DurationTestTools {

    test("ping server with 2 client") {
        val (time, results) = mesureTimeExecutionOf {
            (1 to 5).par.map { x => Source.fromURL("http://google.fr").mkString }
        }

        println(s"time elapsed for ${results.size} requests = $time")

        time shouldBeMinusThan (500 milliseconds)
    }
}

Plutôt que d'utiliser System.currentTimeMillis(), tu ferais pas mieux d'utiliser le StopWatch de Guava ?
Quoique tu n'as peut-être pas besoin d'une précision de fou non plus...

Mais l'avantage est que tu peux passer un Ticker et tu ne dépends donc plus (nécessairement) de System.

Connaissais pas. Je vais jeter un oeil.