1 files changed, 79 insertions, 0 deletions
diff --git a/kamon-core/src/legacy-test/scala/kamon/metric/instrument/GaugeSpec.scala b/kamon-core/src/legacy-test/scala/kamon/metric/instrument/GaugeSpec.scala
new file mode 100644
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+++ b/kamon-core/src/legacy-test/scala/kamon/metric/instrument/GaugeSpec.scala
@@ -0,0 +1,79 @@
+/*
+ * =========================================================================================
+ * Copyright © 2013-2015 the kamon project <http://kamon.io/>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the
+ * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+ * either express or implied. See the License for the specific language governing permissions
+ * and limitations under the License.
+ * =========================================================================================
+ */
+
+package kamon.metric.instrument
+
+import java.util.concurrent.atomic.AtomicLong
+import kamon.Kamon
+import kamon.metric.instrument.Histogram.DynamicRange
+import kamon.testkit.BaseKamonSpec
+import scala.concurrent.duration._
+
+class GaugeSpec extends BaseKamonSpec("gauge-spec") {
+
+  "a Gauge" should {
+    "automatically record the current value using the configured refresh-interval" in new GaugeFixture {
+      val (numberOfValuesRecorded, gauge) = createGauge()
+      Thread.sleep(1.second.toMillis)
+
+      numberOfValuesRecorded.get() should be(10L +- 1L)
+      gauge.cleanup
+    }
+
+    "stop automatically recording after a call to cleanup" in new GaugeFixture {
+      val (numberOfValuesRecorded, gauge) = createGauge()
+      Thread.sleep(1.second.toMillis)
+
+      gauge.cleanup
+      numberOfValuesRecorded.get() should be(10L +- 1L)
+      Thread.sleep(1.second.toMillis)
+
+      numberOfValuesRecorded.get() should be(10L +- 1L)
+    }
+
+    "produce a Histogram snapshot including all the recorded values" in new GaugeFixture {
+      val (numberOfValuesRecorded, gauge) = createGauge()
+
+      Thread.sleep(1.second.toMillis)
+      gauge.cleanup
+      val snapshot = gauge.collect(Kamon.metrics.buildDefaultCollectionContext)
+
+      snapshot.numberOfMeasurements should be(10L +- 1L)
+      snapshot.min should be(1)
+      snapshot.max should be(10L +- 1L)
+    }
+
+    "not record the current value when doing a collection" in new GaugeFixture {
+      val (numberOfValuesRecorded, gauge) = createGauge(10 seconds)
+
+      val snapshot = gauge.collect(Kamon.metrics.buildDefaultCollectionContext)
+      snapshot.numberOfMeasurements should be(0)
+      numberOfValuesRecorded.get() should be(0)
+    }
+  }
+
+  trait GaugeFixture {
+    def createGauge(refreshInterval: FiniteDuration = 100 millis): (AtomicLong, Gauge) = {
+      val recordedValuesCounter = new AtomicLong(0)
+      val gauge = Gauge(DynamicRange(1, 100, 2), refreshInterval, Kamon.metrics.settings.refreshScheduler, {
+        () ⇒ recordedValuesCounter.addAndGet(1)
+      })
+
+      (recordedValuesCounter, gauge)
+    }
+
+  }
+}