update crypto helper and database fixture

Change-Id: I93f81e58e66a0d3cf622b1ec16f514c24aa3c18d
diff --git a/tests/database-fixture.hpp b/tests/database-fixture.hpp
index d737582..598e304 100644
--- a/tests/database-fixture.hpp
+++ b/tests/database-fixture.hpp
@@ -41,7 +41,7 @@
   DatabaseFixture()
   {
     boost::filesystem::path parentDir{TMP_TESTS_PATH};
-    dbDir = parentDir / "test-home/.ndncert";
+    dbDir = parentDir / "test-home" / ".ndncert";
     if (!boost::filesystem::exists(dbDir)) {
       boost::filesystem::create_directory(dbDir);
     }