kamon-core/src/test/scala/kamon/metric/instrument/CounterSpec.scala


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package kamon.metric.instrument

import kamon.LogInterceptor
import kamon.metric.Entity
import kamon.testkit.DefaultInstrumentFactory
import org.scalatest.{Matchers, WordSpec}
import uk.org.lidalia.slf4jext.Level
import uk.org.lidalia.slf4jtest.TestLoggerFactory

class CounterSpec extends WordSpec with Matchers with LogInterceptor with DefaultInstrumentFactory {
  implicit val testLogger = TestLoggerFactory.getTestLogger(classOf[LongAdderCounter])

  "a Counter" should {

    "allow unit and bundled increments" in {
      val counter = buildCounter("unit-increments")
      counter.increment()
      counter.increment()
      counter.increment(40)

      counter.snapshot().value shouldBe(42)
    }

    "warn the user and ignore attempts to decrement the counter" in {
      val counter = buildCounter("attempt-to-decrement")
      counter.increment(100)
      counter.increment(100)
      counter.increment(100)

      interceptLog(Level.WARN) {
        counter.increment(-10L)
      }.head.getMessage() shouldBe(s"Ignored attempt to decrement counter [attempt-to-decrement] on entity [$defaultEntity]")

      counter.snapshot().value shouldBe(300)
    }

    "reset the internal state to zero after taking snapshots" in {
      val counter = buildCounter("reset-after-snapshot")
      counter.increment()
      counter.increment(10)

      counter.snapshot().value shouldBe(11)
      counter.snapshot().value shouldBe(0)
    }
  }
}