tests: TcpTransport test suite improvements

refs #3306

Change-Id: I3b342b4df13db7996b03de7d1bed65b579798f85
diff --git a/tests/daemon/face/get-available-interface-ip.hpp b/tests/daemon/face/get-available-interface-ip.hpp
new file mode 100644
index 0000000..feadabe
--- /dev/null
+++ b/tests/daemon/face/get-available-interface-ip.hpp
@@ -0,0 +1,93 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2015,  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 NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD 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.
+ *
+ * NFD 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
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef NFD_TESTS_DAEMON_FACE_GET_AVAILABLE_INTERFACE_IP_HPP
+#define NFD_TESTS_DAEMON_FACE_GET_AVAILABLE_INTERFACE_IP_HPP
+
+#include "core/network-interface.hpp"
+
+#define SKIP_IF_IP_UNAVAILABLE(address) \
+  do { \
+    if (address.is_unspecified()) { \
+      BOOST_WARN_MESSAGE(false, "skipping assertions that require a valid IP address"); \
+      return; \
+    } \
+  } while (false)
+
+namespace nfd {
+namespace face {
+namespace tests {
+
+/** \brief get a non-local IP address from any available network interface
+ *  \tparam A the address type, either boost::asio::ip::address_v4 or boost::asio::ip::address_v6
+ *  \return an IP address
+ *  \retval default-constructed A, if no address is available
+ */
+template<typename A>
+A
+getAvailableInterfaceIp();
+
+template<>
+boost::asio::ip::address_v4
+getAvailableInterfaceIp()
+{
+  for (const auto& interface : listNetworkInterfaces()) {
+    if (interface.isUp() && !interface.isLoopback()) {
+      for (const auto& address : interface.ipv4Addresses) {
+        if (!address.is_unspecified() &&
+            !address.is_loopback()) {
+          return address;
+        }
+      }
+    }
+  }
+
+  return {};
+}
+
+template<>
+boost::asio::ip::address_v6
+getAvailableInterfaceIp()
+{
+  for (const auto& interface : listNetworkInterfaces()) {
+    if (interface.isUp() && !interface.isLoopback()) {
+      for (const auto& address : interface.ipv6Addresses) {
+        if (!address.is_unspecified() &&
+            !address.is_link_local() && // see #1428
+            !address.is_loopback()) {
+          return address;
+        }
+      }
+    }
+  }
+
+  return {};
+}
+
+} // namespace tests
+} // namespace face
+} // namespace nfd
+
+#endif // NFD_TESTS_DAEMON_FACE_GET_AVAILABLE_INTERFACE_IP_HPP