diff --git a/Modules/Core/Functor/test/otbFunctorImageFilter.cxx b/Modules/Core/Functor/test/otbFunctorImageFilter.cxx
index abb7505006676544ecadebe2817118704c2d808c..e1cd5360e2713ed13d4f5c5761a7b4b58c7ed871 100644
--- a/Modules/Core/Functor/test/otbFunctorImageFilter.cxx
+++ b/Modules/Core/Functor/test/otbFunctorImageFilter.cxx
@@ -101,6 +101,7 @@ template <typename T> struct TypesCheck
   auto filter = NewFunctorFilter(functor);
 
   using FilterType = typename decltype(filter)::ObjectType;
+  static_assert(FilterType::NumberOfInputs == 1,"");
   static_assert(std::is_same<typename FilterType::template InputImageType<0>, InputImageType>::value, "");
 
   filter->SetVInputs(in);