tests: use decorators to disable test data generators by default

Change-Id: I7f58bc4f939a6040f0dab647f07b9c29a4a16b4e
diff --git a/tests/boost-test.hpp b/tests/boost-test.hpp
index dbc5ceb..6812327 100644
--- a/tests/boost-test.hpp
+++ b/tests/boost-test.hpp
@@ -27,4 +27,6 @@
 #define BOOST_TEST_DYN_LINK
 #include <boost/test/unit_test.hpp>
 
+namespace ut = boost::unit_test;
+
 #endif // NDN_NAC_TESTS_BOOST_TEST_HPP