Add forwarding test for 2 arguments.

test/Jamfile.v2

@@ -49,4 +49,5 @@ test-suite "bind"
       [ run mem_fn_unary_addr_test.cpp ]
       [ run bind_function2_test.cpp ]
       [ run bind_fwd_test.cpp ]
+      [ run bind_fwd2_test.cpp ]
     ;

test/bind_fwd2_test.cpp

@@ -0,0 +1,121 @@
+#include <boost/config.hpp>
+
+//
+//  bind_fwd2_test.cpp - forwarding test for 2 arguments
+//
+//  Copyright (c) 2015 Peter Dimov
+//
+//  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
+//
+
+#include <boost/bind.hpp>
+#include <boost/detail/lightweight_test.hpp>
+
+//
+
+int fv1( int const & a )
+{
+    return a;
+}
+
+void fv2_1( int & a, int const & b )
+{
+    a = b;
+}
+
+void fv2_2( int const & a, int & b )
+{
+    b = a;
+}
+
+int fv2_3( int const & a, int const & b )
+{
+    return a+b;
+}
+
+void test()
+{
+    {
+        int const a = 1;
+        int r = boost::bind( fv1, _1 )( a );
+        BOOST_TEST( r == 1 );
+    }
+
+    {
+        int r = boost::bind( fv1, _1 )( 1 );
+        BOOST_TEST( r == 1 );
+    }
+
+    {
+        int a = 1;
+        int const b = 2;
+
+        boost::bind( fv2_1, _1, _2 )( a, b );
+
+        BOOST_TEST( a == 2 );
+    }
+
+    {
+        int a = 1;
+
+        boost::bind( fv2_1, _1, _2 )( a, 2 );
+
+        BOOST_TEST( a == 2 );
+    }
+
+    {
+        int const a = 1;
+        int b = 2;
+
+        boost::bind( fv2_2, _1, _2 )( a, b );
+
+        BOOST_TEST( b == 1 );
+    }
+
+    {
+        int b = 2;
+
+        boost::bind( fv2_2, _1, _2 )( 1, b );
+
+        BOOST_TEST( b == 1 );
+    }
+
+    {
+        int const a = 1;
+        int const b = 2;
+
+        int r = boost::bind( fv2_3, _1, _2 )( a, b );
+
+        BOOST_TEST( r == 3 );
+    }
+
+    {
+        int const a = 1;
+
+        int r = boost::bind( fv2_3, _1, _2 )( a, 2 );
+
+        BOOST_TEST( r == 3 );
+    }
+
+    {
+        int const b = 2;
+
+        int r = boost::bind( fv2_3, _1, _2 )( 1, b );
+
+        BOOST_TEST( r == 3 );
+    }
+
+    {
+        int r = boost::bind( fv2_3, _1, _2 )( 1, 2 );
+
+        BOOST_TEST( r == 3 );
+    }
+}
+
+int main()
+{
+    test();
+    return boost::report_errors();
+}