Use the import rule

[SVN r19968]

test/Jamfile

@@ -1,8 +1,7 @@
 subproject libs/mpl/test ;
 
 # bring in rules for testing
-SEARCH on testing.jam = $(BOOST_BUILD_PATH) ;
-include testing.jam ;
+import testing ;
 
 compile advance.cpp ;
 compile always.cpp ;

test/aux_/Jamfile

@@ -1,8 +1,7 @@
 subproject libs/mpl/test/aux_ ;
 
 # bring in rules for testing
-SEARCH on testing.jam = $(BOOST_BUILD_PATH) ;
-include testing.jam ;
+import testing ;
 
 compile debug_print.cpp ;
 compile has_rebind.cpp ;