helper: ScenarioHelper to simplify writing basic simulation scenarios

Primary use of the ScenarioHelper will be in the unit tests, but it can
also be used to write real simulation scenarios.

Change-Id: I3b8c6370d4e5e35c8b36d91e19aa11d18ab46fdc
diff --git a/tests/unit-tests/tests-common.hpp b/tests/unit-tests/tests-common.hpp
index 1c51eae..e858141 100644
--- a/tests/unit-tests/tests-common.hpp
+++ b/tests/unit-tests/tests-common.hpp
@@ -21,8 +21,10 @@
 #define NDNSIM_TESTS_UNIT_TESTS_TESTS_COMMON_HPP
 
 #include "ns3/core-module.h"
-#include "boost-test.hpp"
 #include "model/ndn-global-router.hpp"
+#include "helper/ndn-scenario-helper.hpp"
+
+#include "boost-test.hpp"
 
 namespace ns3 {
 namespace ndn {
@@ -38,6 +40,11 @@
   }
 };
 
+class ScenarioHelperWithCleanupFixture : public ScenarioHelper, public CleanupFixture
+{
+public:
+};
+
 } // namespace ndn
 } // namespace ns3