tests: in test-publish-async, needed to use namespace func_lib for ref.
diff --git a/tests/test-publish-async.cpp b/tests/test-publish-async.cpp
index 21f48fc..6e2c731 100644
--- a/tests/test-publish-async.cpp
+++ b/tests/test-publish-async.cpp
@@ -18,6 +18,7 @@
 using namespace std;
 using namespace ndn;
 using namespace ndn::ptr_lib;
+using namespace ndn::func_lib;
 
 static uint8_t DEFAULT_PUBLIC_KEY_DER[] = {
 0x30, 0x81, 0x9F, 0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01, 0x05, 0x00, 0x03, 0x81,