diff --git a/tests/test-sec-tpm-file.cpp b/tests/test-sec-tpm-file.cpp
index fd27ae8..a81b794 100644
--- a/tests/test-sec-tpm-file.cpp
+++ b/tests/test-sec-tpm-file.cpp
@@ -14,8 +14,7 @@
 #include <cryptopp/rsa.h>
 
 using namespace std;
-using namespace ndn;
-
+namespace ndn {
 
 BOOST_AUTO_TEST_SUITE(TestSecTpmFile)
 
@@ -67,3 +66,5 @@
 }
 
 BOOST_AUTO_TEST_SUITE_END()
+
+} // namespace ndn