Telemetry / Android: do not crash on GetCpuStats() if the process is gone.

tools/telemetry/telemetry/core/platform/android_platform_backend_unittest.py

Index: tools/telemetry/telemetry/core/platform/android_platform_backend_unittest.py
diff --git a/tools/telemetry/telemetry/core/platform/android_platform_backend_unittest.py b/tools/telemetry/telemetry/core/platform/android_platform_backend_unittest.py
new file mode 100644
index 0000000000000000000000000000000000000000..8bb827383e3408924061ac8194004c14f8fc6297
--- /dev/null
+++ b/tools/telemetry/telemetry/core/platform/android_platform_backend_unittest.py
@@ -0,0 +1,49 @@
+# Copyright 2013 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 unittest
+
+from telemetry.core.platform import android_platform_backend
+from telemetry.unittest import system_stub
+
+
+class MockAdbCommands(object):
+  def __init__(self, mock_content):
+    self.mock_content = mock_content
+
+  def CanAccessProtectedFileContents(self):
+    return True
+
+  # pylint: disable=W0613
+  def GetProtectedFileContents(self, file_name, log_result):
+    return self.mock_content
+
+
+class AndroidPlatformBackendTest(unittest.TestCase):
+  def setUp(self):
+    self._stubs = system_stub.Override(android_platform_backend,
+                                       ['perf_control', 'thermal_throttle'])
+
+  def tearDown(self):
+    self._stubs.Restore()
+
+  def testGetCpuStats(self):
+    proc_stat_content = [
+        '7702 (.android.chrome) S 167 167 0 0 -1 1077936448 '
+        '3247 0 0 0 4 1 0 0 20 0 9 0 5603962 337379328 5867 '
+        '4294967295 1074458624 1074463824 3197495984 3197494152 '
+        '1074767676 0 4612 0 38136 4294967295 0 0 17 0 0 0 0 0 0 '
+        '1074470376 1074470912 1102155776']
+    adb_valid_proc_content = MockAdbCommands(proc_stat_content)
+    backend = android_platform_backend.AndroidPlatformBackend(
+        adb_valid_proc_content, False)
+    cpu_stats = backend.GetCpuStats('7702')
+    self.assertEquals(cpu_stats, {'CpuProcessTime': 5.0})
+
+  def testGetCpuStatsInvalidPID(self):
+    # Mock an empty /proc/pid/stat.
+    adb_empty_proc_stat = MockAdbCommands([])
+    backend = android_platform_backend.AndroidPlatformBackend(
+        adb_empty_proc_stat, False)
+    cpu_stats = backend.GetCpuStats('7702')
+    self.assertEquals(cpu_stats, {})