Data: add a copy constructor and assignment operator to clone the signature pointer.
diff --git a/tests/test-encode-decode-data.cpp b/tests/test-encode-decode-data.cpp
index 078e31c..a123cd8 100644
--- a/tests/test-encode-decode-data.cpp
+++ b/tests/test-encode-decode-data.cpp
@@ -18,8 +18,8 @@
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;