Add unit-tests for NotificationComponent

This includes a few common scenarios and a reproduction of the current behavior
affected by the underlying bug of issue #10575. This is done both to document
the change in behavior, as well as to ensure the behavior of the other scenarios
stays the same before and after the fix is applied.

Author: jschmidt-icinga

test/CMakeLists.txt

@@ -118,6 +118,7 @@ set(base_test_SOURCES
   icinga-notification.cpp
   icinga-perfdata.cpp
   methods-pluginnotificationtask.cpp
+  notification-notificationcomponent.cpp
   remote-certificate-fixture.cpp
   remote-filterutility.cpp
   remote-configpackageutility.cpp
@@ -129,6 +130,7 @@ set(base_test_SOURCES
   $<TARGET_OBJECTS:remote>
   $<TARGET_OBJECTS:icinga>
   $<TARGET_OBJECTS:methods>
+  $<TARGET_OBJECTS:notification>
 )
 
 if(ICINGA2_UNITY_BUILD)

test/icinga-notification.cpp

@@ -5,6 +5,9 @@
 #include "icinga/notificationcommand.hpp"
 #include "icinga/service.hpp"
 #include "icinga/user.hpp"
+#include "config/configcompiler.hpp"
+#include "notification/notificationcomponent.hpp"
+#include "remote/apilistener.hpp"
 #include <BoostTestTargetConfig.h>
 #include <iostream>