Enhance exception throwing with Boost Exception library

Change-Id: I471023fc23ffaebe04d9668426b4c1b03e4962ba
Refs: #2997
diff --git a/tests/unit-tests/util/signal.t.cpp b/tests/unit-tests/util/signal.t.cpp
index 41750c2..153ad91 100644
--- a/tests/unit-tests/util/signal.t.cpp
+++ b/tests/unit-tests/util/signal.t.cpp
@@ -405,14 +405,14 @@
 {
   SignalOwner0 so;
 
-  struct HandlerError
+  struct HandlerError : public std::exception
   {
   };
 
   int hit = 0;
   so.sig.connect([&] {
     ++hit;
-    throw HandlerError();
+    BOOST_THROW_EXCEPTION(HandlerError());
   });
 
   BOOST_CHECK_THROW(so.emitSignal(sig), HandlerError);