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

Change-Id: I255c27b552b32570871a9d5f8bda814ba8723c80
Refs: #2497
diff --git a/tests/unit-tests/data.t.cpp b/tests/unit-tests/data.t.cpp
index aa1a6c8..2940c77 100644
--- a/tests/unit-tests/data.t.cpp
+++ b/tests/unit-tests/data.t.cpp
@@ -358,7 +358,7 @@
     "sha256digest=28bad4b5275bd392dbb670c75cf0b66f13f7942b21e80f55c0e86b374753a548");
 }
 
-BOOST_AUTO_TEST_SUITE_END()
+BOOST_AUTO_TEST_SUITE_END() // TestData
 
 } // namespace tests
 } // namespace ndn