better free port discovery

src/etaoin/api.clj

@@ -1821,9 +1821,9 @@
   Returns a port as an integer."
   [type host]
   (loop [port (or (get-in defaults [type :port])
-                  (util/random-port))]
+                  (util/get-free-port))]
     (if (connectable? host port)
-      (recur (util/random-port))
+      (recur (util/get-free-port))
       port)))
 
 ;;

src/etaoin/util.clj

@@ -35,12 +35,7 @@
   ([tpl & args]
    (error (apply format tpl args))))
 
-(defn random-port
-  "Returns a random port skiping the first 1024 ones."
-  []
-  (let [max-port 65536
-        offset 1024]
-    (-> max-port
-        (- offset)
-        (rand-int)
-        (+ offset))))
+(defn get-free-port []
+  (let [socket (java.net.ServerSocket. 0)]
+    (.close socket)
+    (.getLocalPort socket)))