1 files changed, 61 insertions, 0 deletions
diff --git a/kamon-testkit/src/main/scala/kamon/testkit/SpanInspector.scala b/kamon-testkit/src/main/scala/kamon/testkit/SpanInspector.scala
new file mode 100644
index 00000000..f23fba98
--- /dev/null
+++ b/kamon-testkit/src/main/scala/kamon/testkit/SpanInspector.scala
@@ -0,0 +1,61 @@
+package kamon.testkit
+
+import kamon.trace.{Span, SpanContext}
+import kamon.trace.Span.FinishedSpan
+import kamon.util.Clock
+
+import scala.reflect.ClassTag
+import scala.util.Try
+
+class SpanInspector(span: Span) {
+  private val (realSpan, spanData) = Try {
+    val realSpan = span match {
+      case _: Span.Local => span
+    }
+
+    val spanData = invoke[Span.Local, FinishedSpan](realSpan, "toFinishedSpan", classOf[Long] -> Long.box(Clock.microTimestamp()))
+    (realSpan, spanData)
+  }.getOrElse((null, null))
+
+  def isEmpty: Boolean =
+    realSpan == null
+
+  def spanTag(key: String): Option[Span.TagValue] =
+    spanData.tags.get(key)
+
+  def spanTags(): Map[String, Span.TagValue] =
+    spanData.tags
+
+  def metricTags(): Map[String, String] =
+    getField[Span.Local, Map[String, String]](realSpan, "customMetricTags")
+
+  def startTimestamp(): Long =
+    getField[Span.Local, Long](realSpan, "startTimestampMicros")
+
+  def context(): SpanContext =
+    spanData.context
+
+  def operationName(): String =
+    spanData.operationName
+
+
+
+
+  private def getField[T, R](target: Any, fieldName: String)(implicit classTag: ClassTag[T]): R = {
+    val toFinishedSpanMethod = classTag.runtimeClass.getDeclaredField(fieldName)
+    toFinishedSpanMethod.setAccessible(true)
+    toFinishedSpanMethod.get(target).asInstanceOf[R]
+  }
+
+  private def invoke[T, R](target: Any, fieldName: String, parameters: (Class[_], AnyRef)*)(implicit classTag: ClassTag[T]): R = {
+    val parameterClasses = parameters.map(_._1)
+    val parameterInstances = parameters.map(_._2)
+    val toFinishedSpanMethod = classTag.runtimeClass.getDeclaredMethod(fieldName, parameterClasses: _*)
+    toFinishedSpanMethod.setAccessible(true)
+    toFinishedSpanMethod.invoke(target, parameterInstances: _*).asInstanceOf[R]
+  }
+}
+
+object SpanInspector {
+  def apply(span: Span): SpanInspector = new SpanInspector(span)
+}