COMP: ctkWorkflowTest2 - Fix warning

Libs/Core/Testing/Cpp/ctkExampleWorkflowStepUsingSignalsAndSlots.cpp

@@ -88,7 +88,7 @@ void ctkExampleWorkflowStepUsingSignalsAndSlots::validateFails()const
   // Always returns false in this simple example
   QObject::staticMetaObject.invokeMethod(
       d->Step->ctkWorkflowStepQObject(), "validationComplete",
-      Q_ARG(bool, false));
+        Q_ARG(bool, false), Q_ARG(QString, ""));
 }
 
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