add support for ExternalName service type in dynamic mode

rootfs/etc/nginx/lua/test/run.lua

@@ -0,0 +1,32 @@
+local ffi = require("ffi")
+
+-- without this we get errors such as "attempt to redefine XXX"
+local old_cdef = ffi.cdef
+local exists = {}
+ffi.cdef = function(def)
+  if exists[def] then
+    return
+  end
+  exists[def] = true
+  return old_cdef(def)
+end
+
+local old_udp = ngx.socket.udp
+ngx.socket.udp = function(...)
+  local socket = old_udp(...)
+  socket.send = function(...)
+    error("ngx.socket.udp:send please mock this to use in tests")
+  end
+  return socket
+end
+
+local old_tcp = ngx.socket.tcp
+ngx.socket.tcp = function(...)
+  local socket = old_tcp(...)
+  socket.send = function(...)
+    error("ngx.socket.tcp:send please mock this to use in tests")
+  end
+  return socket
+end
+
+require "busted.runner"({ standalone = false })