Add certificate fetcher of ndns-appcert and ndns-cert

Validators are updated accordingly

Change-Id: Ibdee00b8f20243448a2ba3011ca87f85ce1ea516
diff --git a/tests/dummy-forwarder.hpp b/tests/dummy-forwarder.hpp
new file mode 100644
index 0000000..481d257
--- /dev/null
+++ b/tests/dummy-forwarder.hpp
@@ -0,0 +1,70 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2017,  Regents of the University of California,
+ *                           Arizona Board of Regents,
+ *                           Colorado State University,
+ *                           University Pierre & Marie Curie, Sorbonne University,
+ *                           Washington University in St. Louis,
+ *                           Beijing Institute of Technology,
+ *                           The University of Memphis.
+ *
+ * This file is part of NDNS (Named Data Networking Domain Name Service) and is
+ * based on the code written as part of NFD (Named Data Networking Daemon).
+ * See AUTHORS.md for complete list of NDNS authors and contributors.
+ *
+ * NDNS is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NDNS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NDNS, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <ndn-cxx/interest.hpp>
+#include <ndn-cxx/data.hpp>
+#include <ndn-cxx/lp/nack.hpp>
+#include <ndn-cxx/util/dummy-client-face.hpp>
+#include <ndn-cxx/security/key-chain.hpp>
+
+#ifndef NDNS_TESTS_TEST_DUMMY_FORWARDER_HPP
+#define NDNS_TESTS_TEST_DUMMY_FORWARDER_HPP
+
+namespace ndn {
+namespace ndns {
+namespace tests {
+
+/**
+ * @brief Very basic implementation of the dummy forwarder
+ *
+ * Interests expressed by any added face, will be forwarded to all other faces.
+ * Similarly, any pushed data, will be pushed to all other faces.
+ */
+class DummyForwarder
+{
+public:
+  DummyForwarder(boost::asio::io_service& io, KeyChain& keyChain);
+
+  Face&
+  addFace();
+
+  Face&
+  getFace(size_t nFace)
+  {
+    return *m_faces.at(nFace);
+  }
+
+private:
+  boost::asio::io_service& m_io;
+  KeyChain& m_keyChain;
+  std::vector<shared_ptr<util::DummyClientFace>> m_faces;
+};
+
+} // namespace tests
+} // namespace ndns
+} // namespace ndn
+
+#endif // NDNS_TESTS_TEST_DUMMY_FORWARDER_HPP