[devil] Add system app replacement wrapper script.

devil/devil/android/tools/system_app_devicetest.py

Index: devil/devil/android/tools/system_app_devicetest.py
diff --git a/devil/devil/android/tools/system_app_devicetest.py b/devil/devil/android/tools/system_app_devicetest.py
new file mode 100755
index 0000000000000000000000000000000000000000..0e8afdca560c6134b9f671240b3bf5713438f56a
--- /dev/null
+++ b/devil/devil/android/tools/system_app_devicetest.py
@@ -0,0 +1,98 @@
+#!/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.
+
+import logging
+import os
+import posixpath
+import shutil
+import sys
+import tempfile
+import unittest
+
+if __name__ == '__main__':
+  sys.path.append(
+      os.path.abspath(os.path.join(
+          os.path.dirname(__file__), '..', '..', '..')))
+
+from devil import base_error
+from devil import devil_env
+from devil.android import device_temp_file
+from devil.android import device_test_case
+from devil.android import device_utils
+from devil.android.tools import system_app
+
+logger = logging.getLogger(__name__)
+
+
+class SystemAppDeviceTest(device_test_case.DeviceTestCase):
+
+  PACKAGE = 'com.google.android.webview'
+
+  def setUp(self):
+    super(SystemAppDeviceTest, self).setUp()
+    self._device = device_utils.DeviceUtils(self.serial)
+    self._original_paths = self._device.GetApplicationPaths(self.PACKAGE)
+    self._apk_cache_dir = tempfile.mkdtemp()
+    # Host location -> device location
+    self._cached_apks = {}
+    for o in self._original_paths:
+      h = os.path.join(self._apk_cache_dir, posixpath.basename(o))
+      self._device.PullFile(o, h)
+      self._cached_apks[h] = o
+
+  def tearDown(self):
+    final_paths = self._device.GetApplicationPaths(self.PACKAGE)
+    if self._original_paths != final_paths:
+      try:
+        self._device.Uninstall(self.PACKAGE)
+      except Exception:  # pylint: disable=broad-except
+        pass
+
+      with system_app.EnableSystemAppModification(self._device):
+        for cached_apk, install_path in self._cached_apks.iteritems():
+          try:
+            with device_temp_file.DeviceTempFile(self._device.adb) as tmp:
+              self._device.adb.Push(cached_apk, tmp.name)
+              self._device.RunShellCommand(
+                  ['mv', tmp.name, install_path],
+                  as_root=True, check_return=True)
+          except base_error.BaseError:
+            logger.warning('Failed to reinstall %s',
+                           os.path.basename(cached_apk))
+
+    try:
+      shutil.rmtree(self._apk_cache_dir)
+    except IOError:
+      logger.error('Unable to remove app cache directory.')
+
+    super(SystemAppDeviceTest, self).tearDown()
+
+  def _check_preconditions(self):
+    if not self._original_paths:
+      self.skipTest('%s is not installed on %s' % (
+          self.PACKAGE, str(self._device)))
+    if not any(p.startswith('/system/') for p in self._original_paths):
+      self.skipTest('%s is not installed in a system location on %s' % (
+          self.PACKAGE, str(self._device)))
+
+  def testReplace(self):
+    self._check_preconditions()
+    replacement = devil_env.config.FetchPath(
+        'empty_system_webview', device=self._device)
+    with system_app.ReplaceSystemApp(self._device, self.PACKAGE, replacement):
+      replaced_paths = self._device.GetApplicationPaths(self.PACKAGE)
+      self.assertNotEqual(self._original_paths, replaced_paths)
+    restored_paths = self._device.GetApplicationPaths(self.PACKAGE)
+    self.assertEqual(self._original_paths, restored_paths)
+
+  def testRemove(self):
+    self._check_preconditions()
+    system_app.RemoveSystemApps(self._device, [self.PACKAGE])
+    removed_paths = self._device.GetApplicationPaths(self.PACKAGE)
+    self.assertEqual([], removed_paths)
+
+
+if __name__ == '__main__':
+  unittest.main()