#407 Add a test suite for the singal handler.

pramen/core/src/main/scala/za/co/absa/pramen/core/state/PipelineStateImpl.scala

@@ -258,11 +258,15 @@ class PipelineStateImpl(implicit conf: Config, notificationBuilder: Notification
     }
   }
 
+  private[state] def getFailureException: Option[Throwable] = failureException
+
   private[state] def setSignalException(ex: Throwable): Unit = {
     if (signalException.isEmpty) {
       signalException = Option(ex)
     }
   }
+
+  private[state] def getSignalException: Option[Throwable] = signalException
 }
 
 object PipelineStateImpl {

pramen/core/src/main/scala/za/co/absa/pramen/core/state/PramenSignalHandler.scala

@@ -31,7 +31,7 @@ class PramenSignalHandler(signal: Signal, signalName: String, pipelineState: Pip
   override def handle(sig: Signal): Unit = {
     val stackTraces = Thread.getAllStackTraces.asScala
 
-    val nonDaemonStackTraces = stackTraces.flatMap{ case (t: Thread, s: Array[StackTraceElement]) =>
+    val nonDaemonStackTraces = stackTraces.flatMap { case (t: Thread, s: Array[StackTraceElement]) =>
       if (t.isDaemon) {
         None
       } else {
@@ -54,11 +54,9 @@ class PramenSignalHandler(signal: Signal, signalName: String, pipelineState: Pip
     }
   }
 
-  def setOldSignalHandler(signalHandler: SignalHandler): Unit = {
-    oldHandler = Option(signalHandler)
-  }
+  def setOldSignalHandler(signalHandler: SignalHandler): Unit = oldHandler = Option(signalHandler)
 
-  def unhandle(): Unit = {
-    oldHandler.foreach(handler => Signal.handle(signal, handler))
-  }
+  def getOldSignalHandler: Option[SignalHandler] = oldHandler
+
+  def unhandle(): Unit = oldHandler.foreach(handler => Signal.handle(signal, handler))
 }

pramen/core/src/test/scala/za/co/absa/pramen/core/state/PramenSignalHandlerSuite.scala

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2022 ABSA Group Limited
+ *
+ * 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 za.co.absa.pramen.core.state
+
+import com.typesafe.config.ConfigFactory
+import org.scalatest.wordspec.AnyWordSpec
+import sun.misc.{Signal, SignalHandler}
+
+class PramenSignalHandlerSuite extends AnyWordSpec {
+  private val conf = ConfigFactory.parseString("""pramen.pipeline.name = "test"""")
+    .withFallback(ConfigFactory.load())
+
+  "handle" should {
+    "run the handler and the old handler" in {
+      val notificationBuilder = new NotificationBuilderImpl
+      val stateImpl = new PipelineStateImpl()(conf, notificationBuilder)
+      var reached = false
+
+      val oldSignalHandlerMock = new SignalHandler {
+        override def handle(sig: Signal): Unit = reached = true
+      }
+
+      val signalHandler = new PramenSignalHandler(new Signal("PIPE"), "Interrupt", stateImpl)
+
+      signalHandler.setOldSignalHandler(oldSignalHandlerMock)
+      assert(signalHandler.getOldSignalHandler.get == oldSignalHandlerMock)
+      assert(!reached)
+      Signal.handle(new Signal("PIPE"), signalHandler)
+      signalHandler.handle(null)
+      signalHandler.unhandle()
+      assert(reached)
+      assert(stateImpl.getSignalException.nonEmpty)
+      assert(stateImpl.getFailureException.isEmpty)
+    }
+  }
+
+}