Merge "Do not allow MockWebServer to be played more than once"
diff --git a/src/main/java/com/google/mockwebserver/MockWebServer.java b/src/main/java/com/google/mockwebserver/MockWebServer.java
index 9a89912..31bc2fc 100644
--- a/src/main/java/com/google/mockwebserver/MockWebServer.java
+++ b/src/main/java/com/google/mockwebserver/MockWebServer.java
@@ -184,6 +184,9 @@
      *     specific port is unavailable.
      */
     public void play(int port) throws IOException {
+        if (executor != null) {
+            throw new IllegalStateException("play() already called");
+        }
         executor = Executors.newCachedThreadPool();
         serverSocket = new ServerSocket(port);
         serverSocket.setReuseAddress(true);