Migrate DeviceUtils.parallel to adb_wrapper

The implementation uses AdbWrapper.GetDevices to get the list of
attached devices when needed.

BUG=267773

Review URL: https://codereview.chromium.org/784103005

Cr-Commit-Position: refs/heads/master@{#307670}

2 files changed, 33 insertions, 13 deletions

diff --git a/build/android/pylib/device/device_utils.py b/build/android/pylib/device/device_utils.py
index 553e960..743b1ce 100644
--- a/build/android/pylib/device/device_utils.py
+++ b/build/android/pylib/device/device_utils.py
@@ -1173,8 +1173,8 @@ class DeviceUtils(object):
     """Returns the device serial."""
     return self.adb.GetDeviceSerial()
 
-  @staticmethod
-  def parallel(devices=None, async=False):
+  @classmethod
+  def parallel(cls, devices=None, async=False):
     """Creates a Parallelizer to operate over the provided list of devices.
 
     If |devices| is either |None| or an empty list, the Parallelizer will
@@ -1190,10 +1190,10 @@ class DeviceUtils(object):
     Returns:
       A Parallelizer operating over |devices|.
     """
-    if not devices or len(devices) == 0:
-      devices = pylib.android_commands.GetAttachedDevices()
-    parallelizer_type = (parallelizer.Parallelizer if async
-                         else parallelizer.SyncParallelizer)
-    return parallelizer_type([
-        d if isinstance(d, DeviceUtils) else DeviceUtils(d)
-        for d in devices])
+    if not devices:
+      devices = adb_wrapper.AdbWrapper.GetDevices()
+    devices = [d if isinstance(d, cls) else cls(d) for d in devices]
+    if async:
+      return parallelizer.Parallelizer(devices)
+    else:
+      return parallelizer.SyncParallelizer(devices)
diff --git a/build/android/pylib/device/device_utils_test.py b/build/android/pylib/device/device_utils_test.py
index c451ef3..e396d6e 100755
--- a/build/android/pylib/device/device_utils_test.py
+++ b/build/android/pylib/device/device_utils_test.py
@@ -254,13 +254,18 @@ class DeviceUtilsOldImplTest(unittest.TestCase):
   def tearDown(self):
     self._get_adb_path_patch.stop()
 
+
+def _AdbWrapperMock(test_serial):
+  adb = mock.Mock(spec=adb_wrapper.AdbWrapper)
+  adb.__str__ = mock.Mock(return_value=test_serial)
+  adb.GetDeviceSerial.return_value = test_serial
+  return adb
+
+
 class DeviceUtilsNewImplTest(mock_calls.TestCase):
 
   def setUp(self):
-    test_serial = '0123456789abcdef'
-    self.adb = mock.Mock(spec=adb_wrapper.AdbWrapper)
-    self.adb.__str__ = mock.Mock(return_value=test_serial)
-    self.adb.GetDeviceSerial.return_value = test_serial
+    self.adb = _AdbWrapperMock('0123456789abcdef')
     self.device = device_utils.DeviceUtils(
         self.adb, default_timeout=10, default_retries=0)
     self.watchMethodCalls(self.call.adb, ignore=['GetDeviceSerial'])
@@ -1518,6 +1523,21 @@ class DeviceUtilsStrTest(DeviceUtilsNewImplTest):
       self.assertEqual('0123456789abcdef', str(self.device))
 
 
+class DeviceUtilsParallelTest(mock_calls.TestCase):
+
+  def testParallel_default(self):
+    test_serials = ['0123456789abcdef', 'fedcba9876543210']
+    with self.assertCall(
+        mock.call.pylib.device.adb_wrapper.AdbWrapper.GetDevices(),
+        [_AdbWrapperMock(serial) for serial in test_serials]):
+      parallel_devices = device_utils.DeviceUtils.parallel()
+    for serial, device in zip(test_serials, parallel_devices.pGet(None)):
+      self.assertTrue(
+          isinstance(device, device_utils.DeviceUtils)
+          and serial == str(device),
+          'Expected a DeviceUtils object with serial %s' % serial)
+
+
 if __name__ == '__main__':
   logging.getLogger().setLevel(logging.DEBUG)
   unittest.main(verbosity=2)