diff --git a/tests/test-regex.cpp b/tests/test-regex.cpp
index 75ca0fe..b5d5903 100644
--- a/tests/test-regex.cpp
+++ b/tests/test-regex.cpp
@@ -18,8 +18,8 @@
 
 #include <iostream>
 
-using namespace ndn;
 using namespace std;
+namespace ndn {
 
 BOOST_AUTO_TEST_SUITE(TestRegex)
 
@@ -447,3 +447,5 @@
 }
 
 BOOST_AUTO_TEST_SUITE_END()
+
+} // namespace ndn