diff --git a/tests/test-encode-decode-data.cpp b/tests/test-encode-decode-data.cpp
index 98685a7..0e13d75 100644
--- a/tests/test-encode-decode-data.cpp
+++ b/tests/test-encode-decode-data.cpp
@@ -22,7 +22,7 @@
 #include <cryptopp/files.h>
 
 using namespace std;
-using namespace ndn;
+namespace ndn {
 
 BOOST_AUTO_TEST_SUITE(TestData)
 
@@ -201,3 +201,5 @@
 }
 
 BOOST_AUTO_TEST_SUITE_END()
+
+} // namespace ndn