add tests for active span management

3 files changed, 75 insertions, 7 deletions

diff --git a/kamon-core/src/main/scala/kamon/trace/ActiveSpan.scala b/kamon-core/src/main/scala/kamon/trace/ActiveSpan.scala
index 68ef2254..c30a7157 100644
--- a/kamon-core/src/main/scala/kamon/trace/ActiveSpan.scala
+++ b/kamon-core/src/main/scala/kamon/trace/ActiveSpan.scala
@@ -61,9 +61,6 @@ object ActiveSpan {
     override def setOperationName(operationName: String): Span =
       wrappedSpan.setOperationName(operationName)
 
-    override def finish(): Unit =
-      wrappedSpan.finish()
-
     override def finish(finishMicros: Long): Unit =
       wrappedSpan.finish(finishMicros)
 
diff --git a/kamon-core/src/test/scala/kamon/testkit/SpanInspector.scala b/kamon-core/src/test/scala/kamon/testkit/SpanInspector.scala
index 3ef1012b..e00c8b26 100644
--- a/kamon-core/src/test/scala/kamon/testkit/SpanInspector.scala
+++ b/kamon-core/src/test/scala/kamon/testkit/SpanInspector.scala
@@ -8,7 +8,7 @@ import scala.reflect.ClassTag
 import scala.util.Try
 
 class SpanInspector(span: Span) {
-  private val (realSpan, spanData) = {
+  private val (realSpan, spanData) = Try {
     val realSpan = span match {
       case _: Span.Real => span
       case a: ActiveSpan =>
@@ -17,10 +17,10 @@ class SpanInspector(span: Span) {
 
     val spanData = invoke[Span.Real, FinishedSpan](realSpan, "toFinishedSpan", classOf[Long] -> Long.box(Clock.microTimestamp()))
     (realSpan, spanData)
-  }
+  }.getOrElse((null, null))
 
-  def nonEmpty: Boolean =
-    !span.isInstanceOf[Span.Empty]
+  def isEmpty: Boolean =
+    realSpan == null
 
   def spanTag(key: String): Option[Span.TagValue] =
     spanData.tags.get(key)
diff --git a/kamon-core/src/test/scala/kamon/trace/ActiveSpanManagementSpec.scala b/kamon-core/src/test/scala/kamon/trace/ActiveSpanManagementSpec.scala
new file mode 100644
index 00000000..ebee9f66
--- /dev/null
+++ b/kamon-core/src/test/scala/kamon/trace/ActiveSpanManagementSpec.scala
@@ -0,0 +1,71 @@
+package kamon.trace
+
+import kamon.Kamon
+import kamon.testkit.SpanInspector
+import kamon.trace.Span.Annotation
+import kamon.util.Clock
+import org.scalatest.{Matchers, WordSpec}
+
+class ActiveSpanManagementSpec extends WordSpec with Matchers {
+
+  "Kamon acting as a ActiveSpanSource" should {
+    "return a ActiveSpan wrapping a empty span when there is no currently active Span" in {
+      inspect(Kamon.activeSpan()) shouldBe empty
+    }
+
+    "safely operate on a ActiveSpan that wraps a empty Span" in {
+      val activeSpan = Kamon.activeSpan()
+      val activeSpanData = inspect(Kamon.activeSpan())
+      activeSpanData shouldBe empty
+
+      activeSpan
+        .setOperationName("test")
+        .addBaggage("key", "value")
+        .addMetricTag("key", "value")
+        .addSpanTag("string", "string")
+        .addSpanTag("number", 42)
+        .addSpanTag("boolean-true", true)
+        .addSpanTag("boolean-false", false)
+        .annotate(Annotation(Clock.microTimestamp(), "event", Map("k" -> "v")))
+
+      val baggage = activeSpan.context().baggage
+      baggage.add("key", "value")
+      baggage.get("key") shouldBe empty
+      baggage.getAll() shouldBe empty
+
+      val continuation = activeSpan.capture()
+      val activatedSpan = continuation.activate()
+      inspect(Kamon.activeSpan()) shouldBe empty
+      activatedSpan.deactivate()
+
+      inspect(Kamon.activeSpan()) shouldBe empty
+    }
+
+    "set a Span as active when using makeActive" in {
+      val span = Kamon.buildSpan("mySpan").start()
+      val activeSpan = Kamon.makeActive(span)
+      Kamon.activeSpan() shouldBe theSameInstanceAs(activeSpan)
+      activeSpan.deactivate()
+    }
+
+    "set a Span as active when using startActive" in {
+      val activeSpan = Kamon.buildSpan("mySpan").startActive()
+      Kamon.activeSpan() shouldBe theSameInstanceAs(activeSpan)
+      activeSpan.deactivate()
+    }
+
+    "restore the previously active Span when a ActiveSpan gets deactivated" in {
+      val previouslyActiveSpan = Kamon.activeSpan()
+      inspect(Kamon.activeSpan()) shouldBe empty
+
+      val activeSpan = Kamon.buildSpan("mySpan").startActive()
+      Kamon.activeSpan() shouldBe theSameInstanceAs(activeSpan)
+      activeSpan.deactivate()
+
+      Kamon.activeSpan() shouldBe theSameInstanceAs(previouslyActiveSpan)
+    }
+  }
+
+  def inspect(span: Span): SpanInspector =
+    SpanInspector(span)
+}