package kamon.util
import org.scalatest.{Matchers, WordSpec}
class DifferentialSourceSpec extends WordSpec with Matchers {
"a Differential Source" should {
"get the difference between the last two observations" in {
val source = sourceOf(0, 0, 1, 1, 2, 3, 4, 6, 8, 10, 12, 16, 18)
val expectedDiffs = Seq(0, 1, 0, 1, 1, 1, 2, 2, 2, 2, 4, 2)
values(expectedDiffs.length, source) should contain theSameElementsInOrderAs(expectedDiffs)
}
"ignore decrements in observations" in {
val source = sourceOf(10, 10, 5, 5, 10, 10)
val expectedDiffs = Seq(0, 0, 0, 5, 0)
values(expectedDiffs.length, source) should contain theSameElementsInOrderAs(expectedDiffs)
}
}
def sourceOf(numbers: Long*): DifferentialSource = DifferentialSource(new (() => Long) {
var remaining = numbers.toList
override def apply(): Long = {
if(remaining.isEmpty) 0 else {
val head = remaining.head
remaining = remaining.tail
head
}
}
})
def values(count: Int, source: DifferentialSource): Seq[Long] = {
for(_ <- 1 to count) yield source.get()
}
}