tests: Add partial unit test coverage for Face class

Change-Id: Ica156cae150b8fbb7cb5161765960f248e3eef70
Refs: #1947
diff --git a/tests/integrated/test-faces.cpp b/tests/integrated/test-faces.cpp
index e7ce988..9550286 100644
--- a/tests/integrated/test-faces.cpp
+++ b/tests/integrated/test-faces.cpp
@@ -26,7 +26,7 @@
 #include "boost-test.hpp"
 
 namespace ndn {
-
+namespace tests {
 
 class FacesFixture
 {
@@ -491,6 +491,8 @@
   BOOST_CHECK_EQUAL(nInInterests, 2);
   BOOST_CHECK_EQUAL(nTimeouts, 4);
 }
+
 BOOST_AUTO_TEST_SUITE_END()
 
+} // tests
 } // namespace ndn