Make device serial required in AdbWrapper/DeviceUtils

As a side effect, we also:
- help migrate DeviceUtils.__str__ to AdbWrapper
- fix bug with the presubmit pylib.instrumentation.tests_runner_test
  when no devices are attached.

BUG=267773,430731

Review URL: https://codereview.chromium.org/762883002

Cr-Commit-Position: refs/heads/master@{#306585}

build/android/pylib/device/adb_wrapper.py

@@ -45,6 +45,8 @@ def __init__(self, device_serial):
     Args:
       device_serial: The device serial number as a string.
     """
+    if not device_serial:
+      raise ValueError('A device serial must be specified')
     self._device_serial = str(device_serial)
 
   # pylint: disable=unused-argument

build/android/pylib/device/device_utils.py

@@ -65,8 +65,8 @@ def __init__(self, device, default_timeout=_DEFAULT_TIMEOUT,
     """DeviceUtils constructor.
 
     Args:
-      device: Either a device serial, an existing AdbWrapper instance, an
-              an existing AndroidCommands instance, or nothing.
+      device: Either a device serial, an existing AdbWrapper instance, or an
+              an existing AndroidCommands instance.
       default_timeout: An integer containing the default number of seconds to
                        wait for an operation to complete if no explicit value
                        is provided.
@@ -85,11 +85,8 @@ def __init__(self, device, default_timeout=_DEFAULT_TIMEOUT,
     elif isinstance(device, pylib.android_commands.AndroidCommands):
       self.adb = adb_wrapper.AdbWrapper(device.GetDevice())
       self.old_interface = device
-    elif not device:
-      self.adb = adb_wrapper.AdbWrapper('')
-      self.old_interface = pylib.android_commands.AndroidCommands()
     else:
-      raise ValueError('Unsupported type passed for argument "device"')
+      raise ValueError('Unsupported device value: %r' % device)
     self._commands_installed = None
     self._default_timeout = default_timeout
     self._default_retries = default_retries
@@ -1145,12 +1142,7 @@ def GetMemoryUsageForPid(self, pid, timeout=None, retries=None):
 
   def __str__(self):
     """Returns the device serial."""
-    s = self.old_interface.GetDevice()
-    if not s:
-      s = self.old_interface.Adb().GetSerialNumber()
-      if s == 'unknown':
-        raise device_errors.NoDevicesError()
-    return s
+    return self.adb.GetDeviceSerial()
 
   @staticmethod
   def parallel(devices=None, async=False):

build/android/pylib/device/device_utils_test.py

@@ -43,28 +43,30 @@ class DeviceUtilsTest(unittest.TestCase):
   def testInitWithStr(self):
     serial_as_str = str('0123456789abcdef')
     d = device_utils.DeviceUtils('0123456789abcdef')
-    self.assertEqual(serial_as_str, d.old_interface.GetDevice())
+    self.assertEqual(serial_as_str, d.adb.GetDeviceSerial())
 
   def testInitWithUnicode(self):
     serial_as_unicode = unicode('fedcba9876543210')
     d = device_utils.DeviceUtils(serial_as_unicode)
-    self.assertEqual(serial_as_unicode, d.old_interface.GetDevice())
+    self.assertEqual(serial_as_unicode, d.adb.GetDeviceSerial())
 
   def testInitWithAdbWrapper(self):
     serial = '123456789abcdef0'
     a = adb_wrapper.AdbWrapper(serial)
     d = device_utils.DeviceUtils(a)
-    self.assertEqual(serial, d.old_interface.GetDevice())
+    self.assertEqual(serial, d.adb.GetDeviceSerial())
 
   def testInitWithAndroidCommands(self):
     serial = '0fedcba987654321'
     a = android_commands.AndroidCommands(device=serial)
     d = device_utils.DeviceUtils(a)
-    self.assertEqual(serial, d.old_interface.GetDevice())
+    self.assertEqual(serial, d.adb.GetDeviceSerial())
 
-  def testInitWithNone(self):
-    d = device_utils.DeviceUtils(None)
-    self.assertIsNone(d.old_interface.GetDevice())
+  def testInitWithMissing_fails(self):
+    with self.assertRaises(ValueError):
+      device_utils.DeviceUtils(None)
+    with self.assertRaises(ValueError):
+      device_utils.DeviceUtils('')
 
 
 class MockTempFile(object):
@@ -246,7 +248,7 @@ def setUp(self):
     self.adb.GetDeviceSerial.return_value = test_serial
     self.device = device_utils.DeviceUtils(
         self.adb, default_timeout=10, default_retries=0)
-    self.watchMethodCalls(self.call.adb)
+    self.watchMethodCalls(self.call.adb, ignore=['GetDeviceSerial'])
 
   def ShellError(self, output=None, exit_code=1):
     def action(cmd, *args, **kwargs):
@@ -1524,23 +1526,13 @@ def testGetMemoryUsageForPid_invalidPid(self):
       self.assertEqual({}, self.device.GetMemoryUsageForPid(4321))
 
 
-class DeviceUtilsStrTest(DeviceUtilsOldImplTest):
+class DeviceUtilsStrTest(DeviceUtilsNewImplTest):
 
-  def testStr_noAdbCalls(self):
-    with self.assertNoAdbCalls():
-      self.assertEqual('0123456789abcdef', str(self.device))
-
-  def testStr_noSerial(self):
-    self.device = device_utils.DeviceUtils(None)
-    with self.assertCalls('adb  get-serialno', '0123456789abcdef'):
+  def testStr_returnsSerial(self):
+    with self.assertCalls(
+        (self.call.adb.GetDeviceSerial(), '0123456789abcdef')):
       self.assertEqual('0123456789abcdef', str(self.device))
 
-  def testStr_noSerial_noDevices(self):
-    self.device = device_utils.DeviceUtils(None)
-    with self.assertCalls('adb  get-serialno', 'unknown'), (
-         self.assertRaises(device_errors.NoDevicesError)):
-      str(self.device)
-
 
 if __name__ == '__main__':
   logging.getLogger().setLevel(logging.DEBUG)

build/android/pylib/instrumentation/test_runner_test.py

@@ -27,7 +27,8 @@ def setUp(self):
     options = mock.Mock()
     options.tool = ''
     package = mock.Mock()
-    self.instance = test_runner.TestRunner(options, None, 0, package)
+    self.instance = test_runner.TestRunner(
+        options, '123456789abcdef0', 0, package)
 
   def testParseAmInstrumentRawOutput_nothing(self):
     code, result, statuses = (
@@ -226,6 +227,8 @@ def testGenerateTestResult_testFailed(self):
         'test': ['testMethod'],
       }),
     ]
+    self.instance.device.old_interface.DismissCrashDialogIfNeeded = mock.Mock(
+        return_value=None)
     result = self.instance._GenerateTestResult(
         'test.package.TestClass#testMethod', statuses, 0, 1000)
     self.assertEqual(base_test_result.ResultType.FAIL, result.GetType())

build/android/pylib/utils/mock_calls.py

@@ -122,16 +122,19 @@ def watchCalls(self, calls):
     """
     self._watched.update((call.name, call) for call in calls)
 
-  def watchMethodCalls(self, call):
+  def watchMethodCalls(self, call, ignore=None):
     """Watch all public methods of the target identified by a self.call.
 
     Args:
       call: a self.call instance indetifying an object
+      ignore: a list of public methods to ignore when watching for calls
     """
     target = self.call_target(call)
+    if ignore is None:
+      ignore = []
     self.watchCalls(getattr(call, method)
                     for method in dir(target.__class__)
-                    if not method.startswith('_'))
+                    if not method.startswith('_') and not method in ignore)
 
   def clearWatched(self):
     """Clear the set of watched calls."""