Data: add a copy constructor and assignment operator to clone the signature pointer.
diff --git a/tests/test-get-async.cpp b/tests/test-get-async.cpp
index 9cdf28a..d59d611 100644
--- a/tests/test-get-async.cpp
+++ b/tests/test-get-async.cpp
@@ -11,8 +11,8 @@
using namespace std;
using namespace ndn;
-using namespace ptr_lib;
-using namespace func_lib;
+using namespace ndn::ptr_lib;
+using namespace ndn::func_lib;
#if NDN_CPP_HAVE_STD_FUNCTION
// In the std library, the placeholders are in a different namespace than boost.
using namespace func_lib::placeholders;