Akka/Scala example source code file (MetricsKitSpec.scala)

This example Akka source code file (MetricsKitSpec.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Akka and Scala source code examples by using tags.

All credit for the original source code belongs to akka.io; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Akka tags/keywords

akka, beforeandafter, beforeandafterall, gauge, kitkey, list, matchers, metrics, metricskit, metricskitspec, test, testing, testkit, utilities, wordspec

The MetricsKitSpec.scala Akka example source code

/**
 * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
 */
package akka.testkit.metrics

import org.scalatest._
import com.typesafe.config.ConfigFactory
import scala.util.Random
import org.scalautils.Tolerance

class MetricsKitSpec extends WordSpec with Matchers with BeforeAndAfter with BeforeAndAfterAll
  with MetricsKit {

  import scala.concurrent.duration._

  override def metricsConfig = ConfigFactory.load()

  val KitKey = MetricKey.fromString("metrics-kit")

  after {
    clearMetrics()
  }

  override def afterAll() {
    shutdownMetrics()
  }

  "MetricsKit" must {

    "allow measuring file descriptor usage" in {
      measureFileDescriptors(KitKey / "file-desc")

      registeredMetrics.count(_._1 contains "file-descriptor") should be > 0
    }

    "allow to measure time, on known number of operations" in {
      timedWithKnownOps(KitKey, ops = 10) {
        2 + 2
      }
    }

    "allow to measure average value using Gauge, given multiple values" in {
      val sizes = List(1L, 2L, 3L)

      val avg = averageGauge(KitKey / "avg-size")

      avg.add(sizes)
      avg.add(4)

      avg.getValue should equal(2.5)
    }

    "measure values in histogram" in {
      val maxMillis = 100.millis.toNanos
      val hist = hdrHistogram(KitKey / "hist", highestTrackableValue = maxMillis, 4, "ns")

      for {
        n ← 1 to 11
        i ← 0L to 1579331
      } hist.update(i)

      hist.update(1579331)
      reportMetrics()
    }

    "fail with human readable error when the histogram overflowed" in {
      val maxMillis = 100.millis.toNanos
      val hist = hdrHistogram(KitKey / "hist", highestTrackableValue = maxMillis, 4, "ns")

      val ex = intercept[IllegalArgumentException] {
        hist.update(10.second.toNanos)
      }

      ex.getMessage should include("can not be stored in this histogram")
    }

  }

}