Adding test cases for a scenario of increased arity limit

Test cases are based on calling apply to forward to the and_ predicate
an increasing number, from 2 to 15, of true_ constants. Since the arity
limit on the current version is set to 5,
BOOST_MPL_LIMIT_METAFUNCTION_ARITY and
BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS must be appropriately set.

test/aux_/increased_arity.cpp

@@ -0,0 +1,50 @@
+
+// Copyright Bruno Dutra 2015
+//
+// Distributed under the Boost Software License, Version 1.0. 
+// (See accompanying file LICENSE_1_0.txt or copy at 
+// http://www.boost.org/LICENSE_1_0.txt)
+//
+// See http://www.boost.org/libs/mpl for documentation.
+
+// $Id$
+// $Date$
+// $Revision$
+
+#define BOOST_MPL_LIMIT_METAFUNCTION_ARITY 15
+#define BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS
+
+#include <boost/mpl/logical.hpp>
+#include <boost/mpl/placeholders.hpp>
+#include <boost/mpl/apply.hpp>
+
+#include <boost/mpl/aux_/test.hpp>
+
+#include <boost/preprocessor/cat.hpp>
+#include <boost/preprocessor/inc.hpp>
+#include <boost/preprocessor/repeat_from_to.hpp>
+#include <boost/preprocessor/enum_params.hpp>
+#include <boost/preprocessor/enum_shifted_params.hpp>
+#include <boost/preprocessor/facilities/intercept.hpp>
+
+#define TEST_N_ARY(unused1, N, unused2) \
+    struct BOOST_PP_CAT(_, BOOST_PP_CAT(N, _ary)) \
+    { \
+        MPL_ASSERT(( \
+                apply< \
+                    and_<BOOST_PP_ENUM_SHIFTED_PARAMS(BOOST_PP_INC(N), _)>, \
+                    BOOST_PP_ENUM_PARAMS(N, true_ BOOST_PP_INTERCEPT) \
+                > \
+            )); \
+    }; \
+/**/
+
+MPL_TEST_CASE()
+{
+    BOOST_PP_REPEAT_FROM_TO(
+            2,
+            BOOST_PP_INC(BOOST_MPL_LIMIT_METAFUNCTION_ARITY),
+            TEST_N_ARY,
+            _
+        )
+}