diff --git a/src/libraries/turtle/constraint.hpp b/src/libraries/turtle/constraint.hpp
index dabe4a2..5ed410d 100644
--- a/src/libraries/turtle/constraint.hpp
+++ b/src/libraries/turtle/constraint.hpp
@@ -9,8 +9,6 @@
 #ifndef MOCK_PLACEHOLDER_HPP_INCLUDED
 #define MOCK_PLACEHOLDER_HPP_INCLUDED
 
-#include "format.hpp"
-
 namespace mock
 {
     template< typename Constraint >
diff --git a/src/libraries/turtle/constraints.hpp b/src/libraries/turtle/constraints.hpp
index 2d7f81b..bf7866f 100644
--- a/src/libraries/turtle/constraints.hpp
+++ b/src/libraries/turtle/constraints.hpp
@@ -10,6 +10,7 @@
 #define MOCK_CONSTRAINTS_HPP_INCLUDED
 
 #include "constraint.hpp"
+#include "format.hpp"
 #include <boost/utility/enable_if.hpp>
 #include <boost/type_traits/is_convertible.hpp>
 #include <boost/algorithm/string/predicate.hpp>