diff --git a/turtle/detail/function_impl_template.hpp b/turtle/detail/function_impl_template.hpp
index bede0c8..68c8259 100644
--- a/turtle/detail/function_impl_template.hpp
+++ b/turtle/detail/function_impl_template.hpp
@@ -127,6 +127,17 @@ namespace detail
             return error_type::abort();
         }
 
+        void add( context& c, const void* p,
+            boost::unit_test::const_string instance,
+            boost::optional< type_name > type,
+            boost::unit_test::const_string name )
+        {
+            if( ! context_ )
+                c.add( *this );
+            c.add( p, *this, instance, type, name );
+            context_ = &c;
+        }
+
         friend std::ostream& operator<<(
             std::ostream& s, const function_impl& impl )
         {
diff --git a/turtle/detail/function_template.hpp b/turtle/detail/function_template.hpp
index 1b59ee3..bbab134 100644
--- a/turtle/detail/function_template.hpp
+++ b/turtle/detail/function_template.hpp
@@ -89,10 +89,7 @@ namespace detail
         function& operator()( context& c,
             boost::unit_test::const_string instance )
         {
-            if( ! impl_->context_ )
-                c.add( *impl_ );
-            c.add( impl_.get(), *impl_, instance, boost::none, "" );
-            impl_->context_ = &c;
+            impl_->add( c, impl_.get(), instance, boost::none, "" );
             return *this;
         }
 
@@ -101,10 +98,7 @@ namespace detail
             boost::optional< type_name > type,
             boost::unit_test::const_string name ) const
         {
-            if( ! impl_->context_ )
-                c.add( *impl_ );
-            c.add( p, *impl_, instance, type, name );
-            impl_->context_ = &c;
+            impl_->add( c, p, instance, type, name );
         }
 
     private: