test: basic unit-test for WebSocket face

Change-Id: I41dcc2ecff57225db1aff8e359d507f0e89d4c96
Refs: #1553
diff --git a/daemon/face/websocket-channel.hpp b/daemon/face/websocket-channel.hpp
index 05d8f99..62c4940 100644
--- a/daemon/face/websocket-channel.hpp
+++ b/daemon/face/websocket-channel.hpp
@@ -85,6 +85,9 @@
   size_t
   size() const;
 
+  bool
+  isListening() const;
+
 private:
   void
   handleMessage(websocketpp::connection_hdl hdl, websocket::Server::message_ptr msg);
@@ -117,6 +120,12 @@
 
 };
 
+inline bool
+WebSocketChannel::isListening() const
+{
+  return m_isListening;
+}
+
 } // namespace nfd
 
 #endif // NFD_DAEMON_FACE_WEBSOCKET_CHANNEL_HPP