devil: Raise DeviceUnreachableError on cmd output "waiting for device"

devil/devil/android/sdk/adb_wrapper_test.py

 #!/usr/bin/env python
 # Copyright 2017 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 Unit tests for some APIs with conditional logic in adb_wrapper.py
 """
 
 import unittest
 
 from devil import devil_env
 from devil.android import device_errors
 from devil.android.sdk import adb_wrapper
 
 with devil_env.SysPath(devil_env.PYMOCK_PATH):
   import mock  # pylint: disable=import-error
 
 
 class AdbWrapperTest(unittest.TestCase):
   def setUp(self):
-    self.adb = adb_wrapper.AdbWrapper('ABC12345678')
+    self.device_serial = 'ABC12345678'
+    self.adb = adb_wrapper.AdbWrapper(self.device_serial)
 
   def _MockRunDeviceAdbCmd(self, return_value):
     return mock.patch.object(
         self.adb,
         '_RunDeviceAdbCmd',
         mock.Mock(side_effect=None, return_value=return_value))
 
   def testDisableVerityWhenDisabled(self):
     with self._MockRunDeviceAdbCmd('Verity already disabled on /system'):
       self.adb.DisableVerity()
@@ skipping 17 matching lines @@
   def testFailEnableVerity(self):
     with self._MockRunDeviceAdbCmd('error: closed'):
       self.assertRaises(
           device_errors.AdbCommandFailedError, self.adb.EnableVerity)
 
   def testFailDisableVerity(self):
     with self._MockRunDeviceAdbCmd('error: closed'):
       self.assertRaises(
           device_errors.AdbCommandFailedError, self.adb.DisableVerity)
 
+  @mock.patch('devil.utils.cmd_helper.GetCmdStatusAndOutputWithTimeout')
+  def testDeviceUnreachable(self, get_cmd_mock):
+    get_cmd_mock.return_value = (
+        1, "error: device '%s' not found" % self.device_serial)
+    self.assertRaises(
+        device_errors.DeviceUnreachableError, self.adb.Shell, '/bin/true')
+
+  @mock.patch('devil.utils.cmd_helper.GetCmdStatusAndOutputWithTimeout')
+  def testWaitingForDevice(self, get_cmd_mock):
+    get_cmd_mock.return_value = (1, '- waiting for device - ')
+    self.assertRaises(
+        device_errors.DeviceUnreachableError, self.adb.Shell, '/bin/true')