storage: skiplist for repo index

This version of skiplist is low efficient because of the map in it

Change-Id: Idecc9016619ca9ab5cbb17b078f71b1cc3d4b03e
refs #1737
diff --git a/tests/dataset-fixtures.hpp b/tests/dataset-fixtures.hpp
index 3adf0b4..3cc2685 100644
--- a/tests/dataset-fixtures.hpp
+++ b/tests/dataset-fixtures.hpp
@@ -50,6 +50,23 @@
 
   typedef std::list<std::pair<ndn::Interest, ndn::shared_ptr<ndn::Data> > > InterestContainer;
   InterestContainer interests;
+
+
+  struct DataSetNameCompare
+  {
+    bool operator()(const ndn::Name& a, const ndn::Name& b) const
+    {
+      return a < b;
+    }
+  };
+
+  struct DataSetDataCompare
+  {
+    bool operator()(const Data& a, const Data& b) const
+    {
+      return a.getName() < b.getName();
+    }
+  };
 };