diff --git a/include/boost/unordered/detail/fwd.hpp b/include/boost/unordered/detail/fwd.hpp
index acaa8f11..7fcb770e 100644
--- a/include/boost/unordered/detail/fwd.hpp
+++ b/include/boost/unordered/detail/fwd.hpp
@@ -61,4 +61,90 @@ namespace boost {
   }
 }
 
+// BOOST_UNORDERED_EMPLACE_LIMIT = The maximum number of parameters in
+// emplace (not including things like hints). Don't set it to a lower value, as
+// that might break something.
+
+#if !defined BOOST_UNORDERED_EMPLACE_LIMIT
+#define BOOST_UNORDERED_EMPLACE_LIMIT 10
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+// Configuration
+//
+// Unless documented elsewhere these configuration macros should be considered
+// an implementation detail, I'll try not to break them, but you never know.
+
+// Use Sun C++ workarounds
+// I'm not sure which versions of the compiler require these workarounds, so
+// I'm just using them of everything older than the current test compilers
+// (as of May 2017).
+
+#if !defined(BOOST_UNORDERED_SUN_WORKAROUNDS1)
+#if BOOST_COMP_SUNPRO && BOOST_COMP_SUNPRO < BOOST_VERSION_NUMBER(5, 20, 0)
+#define BOOST_UNORDERED_SUN_WORKAROUNDS1 1
+#else
+#define BOOST_UNORDERED_SUN_WORKAROUNDS1 0
+#endif
+#endif
+
+// BOOST_UNORDERED_TUPLE_ARGS
+//
+// Maximum number of std::tuple members to support, or 0 if std::tuple
+// isn't avaiable. More are supported when full C++11 is used.
+
+// Already defined, so do nothing
+#if defined(BOOST_UNORDERED_TUPLE_ARGS)
+
+// Assume if we have C++11 tuple it's properly variadic,
+// and just use a max number of 10 arguments.
+#elif !defined(BOOST_NO_CXX11_HDR_TUPLE)
+#define BOOST_UNORDERED_TUPLE_ARGS 10
+
+// Visual C++ has a decent enough tuple for piecewise construction,
+// so use that if available, using _VARIADIC_MAX for the maximum
+// number of parameters. Note that this comes after the check
+// for a full C++11 tuple.
+#elif defined(BOOST_MSVC)
+#if !BOOST_UNORDERED_HAVE_PIECEWISE_CONSTRUCT
+#define BOOST_UNORDERED_TUPLE_ARGS 0
+#elif defined(_VARIADIC_MAX)
+#define BOOST_UNORDERED_TUPLE_ARGS _VARIADIC_MAX
+#else
+#define BOOST_UNORDERED_TUPLE_ARGS 5
+#endif
+
+// Assume that we don't have std::tuple
+#else
+#define BOOST_UNORDERED_TUPLE_ARGS 0
+#endif
+
+#if BOOST_UNORDERED_TUPLE_ARGS
+#include <tuple>
+#endif
+
+// BOOST_UNORDERED_CXX11_CONSTRUCTION
+//
+// Use C++11 construction, requires variadic arguments, good construct support
+// in allocator_traits and piecewise construction of std::pair
+// Otherwise allocators aren't used for construction/destruction
+
+#if BOOST_UNORDERED_HAVE_PIECEWISE_CONSTRUCT &&                                \
+  !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) && BOOST_UNORDERED_TUPLE_ARGS
+#if BOOST_COMP_SUNPRO && BOOST_LIB_STD_GNU
+// Sun C++ std::pair piecewise construction doesn't seem to be exception safe.
+// (At least for Sun C++ 12.5 using libstdc++).
+#define BOOST_UNORDERED_CXX11_CONSTRUCTION 0
+#elif BOOST_COMP_GNUC && BOOST_COMP_GNUC < BOOST_VERSION_NUMBER(4, 7, 0)
+// Piecewise construction in GCC 4.6 doesn't work for uncopyable types.
+#define BOOST_UNORDERED_CXX11_CONSTRUCTION 0
+#elif !defined(BOOST_NO_CXX11_ALLOCATOR)
+#define BOOST_UNORDERED_CXX11_CONSTRUCTION 1
+#endif
+#endif
+
+#if !defined(BOOST_UNORDERED_CXX11_CONSTRUCTION)
+#define BOOST_UNORDERED_CXX11_CONSTRUCTION 0
+#endif
+
 #endif
diff --git a/include/boost/unordered/detail/implementation.hpp b/include/boost/unordered/detail/implementation.hpp
index 13351171..68f312a5 100644
--- a/include/boost/unordered/detail/implementation.hpp
+++ b/include/boost/unordered/detail/implementation.hpp
@@ -60,92 +60,6 @@
 #include <type_traits>
 #endif
 
-////////////////////////////////////////////////////////////////////////////////
-// Configuration
-//
-// Unless documented elsewhere these configuration macros should be considered
-// an implementation detail, I'll try not to break them, but you never know.
-
-// Use Sun C++ workarounds
-// I'm not sure which versions of the compiler require these workarounds, so
-// I'm just using them of everything older than the current test compilers
-// (as of May 2017).
-
-#if !defined(BOOST_UNORDERED_SUN_WORKAROUNDS1)
-#if BOOST_COMP_SUNPRO && BOOST_COMP_SUNPRO < BOOST_VERSION_NUMBER(5, 20, 0)
-#define BOOST_UNORDERED_SUN_WORKAROUNDS1 1
-#else
-#define BOOST_UNORDERED_SUN_WORKAROUNDS1 0
-#endif
-#endif
-
-// BOOST_UNORDERED_EMPLACE_LIMIT = The maximum number of parameters in
-// emplace (not including things like hints). Don't set it to a lower value, as
-// that might break something.
-
-#if !defined BOOST_UNORDERED_EMPLACE_LIMIT
-#define BOOST_UNORDERED_EMPLACE_LIMIT 10
-#endif
-
-// BOOST_UNORDERED_TUPLE_ARGS
-//
-// Maximum number of std::tuple members to support, or 0 if std::tuple
-// isn't avaiable. More are supported when full C++11 is used.
-
-// Already defined, so do nothing
-#if defined(BOOST_UNORDERED_TUPLE_ARGS)
-
-// Assume if we have C++11 tuple it's properly variadic,
-// and just use a max number of 10 arguments.
-#elif !defined(BOOST_NO_CXX11_HDR_TUPLE)
-#define BOOST_UNORDERED_TUPLE_ARGS 10
-
-// Visual C++ has a decent enough tuple for piecewise construction,
-// so use that if available, using _VARIADIC_MAX for the maximum
-// number of parameters. Note that this comes after the check
-// for a full C++11 tuple.
-#elif defined(BOOST_MSVC)
-#if !BOOST_UNORDERED_HAVE_PIECEWISE_CONSTRUCT
-#define BOOST_UNORDERED_TUPLE_ARGS 0
-#elif defined(_VARIADIC_MAX)
-#define BOOST_UNORDERED_TUPLE_ARGS _VARIADIC_MAX
-#else
-#define BOOST_UNORDERED_TUPLE_ARGS 5
-#endif
-
-// Assume that we don't have std::tuple
-#else
-#define BOOST_UNORDERED_TUPLE_ARGS 0
-#endif
-
-#if BOOST_UNORDERED_TUPLE_ARGS
-#include <tuple>
-#endif
-
-// BOOST_UNORDERED_CXX11_CONSTRUCTION
-//
-// Use C++11 construction, requires variadic arguments, good construct support
-// in allocator_traits and piecewise construction of std::pair
-// Otherwise allocators aren't used for construction/destruction
-
-#if BOOST_UNORDERED_HAVE_PIECEWISE_CONSTRUCT &&                                \
-  !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) && BOOST_UNORDERED_TUPLE_ARGS
-#if BOOST_COMP_SUNPRO && BOOST_LIB_STD_GNU
-// Sun C++ std::pair piecewise construction doesn't seem to be exception safe.
-// (At least for Sun C++ 12.5 using libstdc++).
-#define BOOST_UNORDERED_CXX11_CONSTRUCTION 0
-#elif BOOST_COMP_GNUC && BOOST_COMP_GNUC < BOOST_VERSION_NUMBER(4, 7, 0)
-// Piecewise construction in GCC 4.6 doesn't work for uncopyable types.
-#define BOOST_UNORDERED_CXX11_CONSTRUCTION 0
-#elif !defined(BOOST_NO_CXX11_ALLOCATOR)
-#define BOOST_UNORDERED_CXX11_CONSTRUCTION 1
-#endif
-#endif
-
-#if !defined(BOOST_UNORDERED_CXX11_CONSTRUCTION)
-#define BOOST_UNORDERED_CXX11_CONSTRUCTION 0
-#endif
-
 #if BOOST_UNORDERED_CXX11_CONSTRUCTION
 #include <boost/mp11/list.hpp>
 #include <boost/mp11/algorithm.hpp>
diff --git a/test/helpers/test.hpp b/test/helpers/test.hpp
index dabd7c24..3417178d 100644
--- a/test/helpers/test.hpp
+++ b/test/helpers/test.hpp
@@ -6,6 +6,7 @@
 #if !defined(BOOST_UNORDERED_TEST_TEST_HEADER)
 #define BOOST_UNORDERED_TEST_TEST_HEADER
 
+#include <boost/unordered/detail/fwd.hpp>
 #include <boost/core/lightweight_test.hpp>
 #include <boost/preprocessor/cat.hpp>
 #include <boost/preprocessor/stringize.hpp>