tests: respect naming conventions and improve nesting of some test suites

Change-Id: I255c27b552b32570871a9d5f8bda814ba8723c80
Refs: #2497
diff --git a/tests/unit-tests/security/signing-info.t.cpp b/tests/unit-tests/security/signing-info.t.cpp
index 994cb2a..e7e1447 100644
--- a/tests/unit-tests/security/signing-info.t.cpp
+++ b/tests/unit-tests/security/signing-info.t.cpp
@@ -22,16 +22,17 @@
 #include "security/signing-info.hpp"
 #include "security/key-chain.hpp"
 
-#include <sstream>
-#include <boost/lexical_cast.hpp>
-
 #include "boost-test.hpp"
 
+#include <boost/lexical_cast.hpp>
+#include <sstream>
+
 namespace ndn {
 namespace security {
 namespace tests {
 
-BOOST_AUTO_TEST_SUITE(SecuritySigningInfo)
+BOOST_AUTO_TEST_SUITE(Security)
+BOOST_AUTO_TEST_SUITE(TestSigningInfo)
 
 BOOST_AUTO_TEST_CASE(Basic)
 {
@@ -151,7 +152,8 @@
                     "id:/localhost/identity/digest-sha256");
 }
 
-BOOST_AUTO_TEST_SUITE_END()
+BOOST_AUTO_TEST_SUITE_END() // TestSigningInfo
+BOOST_AUTO_TEST_SUITE_END() // Security
 
 } // namespace tests
 } // namespace security