add namespace for requester

Change-Id: I3de037dffd702edff9f87a87e8e684161db3d329
diff --git a/tests/unit-tests/requester.t.cpp b/tests/unit-tests/requester.t.cpp
index c67b8fe..16197b4 100644
--- a/tests/unit-tests/requester.t.cpp
+++ b/tests/unit-tests/requester.t.cpp
@@ -29,6 +29,8 @@
 namespace ndncert {
 namespace tests {
 
+using namespace requester;
+
 BOOST_FIXTURE_TEST_SUITE(TestRequester, IdentityManagementTimeFixture)
 
 /* PROBE */