Add a test of EC wake source

This test checks when system is suspended, EC can correctly wake the
system when power button pressed or lid opened.

BUG=chrome-os-partner:9188
TEST=Test passed. See DUT suspended and resumed during test.

Change-Id: I469dc788242c9970dbdae9197bef48c624f173bc
Reviewed-on: https://gerrit.chromium.org/gerrit/23479
Reviewed-by: Tom Wai-Hong Tam <waihong@chromium.org>
Commit-Ready: Vic Yang <victoryang@chromium.org>
Tested-by: Vic Yang <victoryang@chromium.org>
diff --git a/server/cros/servo_test.py b/server/cros/servo_test.py
index d0afc68..e9f9fd9 100644
--- a/server/cros/servo_test.py
+++ b/server/cros/servo_test.py
@@ -253,9 +253,8 @@
         logging.info('Server: Client machine is offline.')
 
 
-    def cleanup(self):
-        """Delete the Servo object, call remote cleanup, and kill ssh."""
-        self._release_servo()
+    def kill_remote(self):
+        """Call remote cleanup and kill ssh."""
         for info in self._remote_infos.itervalues():
             if info['remote_process'] and info['remote_process'].poll() is None:
                 remote_object = getattr(self, info['ref_name'])
@@ -263,6 +262,12 @@
         self._terminate_all_ssh()
 
 
+    def cleanup(self):
+        """Delete the Servo object, call remote cleanup, and kill ssh."""
+        self._release_servo()
+        self.kill_remote()
+
+
     def _launch_ssh_tunnel(self, info):
         """Establish an ssh tunnel for connecting to the remote RPC server.