[Telemetry] Fix android unittests that run after AndroidBrowserFinderTest.

It was leaving the CanFindAvailableBrowsers method in a bad state.

BUG=337829

Review URL: https://codereview.chromium.org/436963003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287184 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 35 insertions, 44 deletions

diff --git a/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py b/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py
index 7389452..8c4adb1 100644
--- a/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py
+++ b/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py
@@ -63,11 +63,6 @@ CHROME_PACKAGE_NAMES = {
 
 ALL_BROWSER_TYPES = CHROME_PACKAGE_NAMES.keys()
 
-# adb shell pm list packages
-# adb
-# intents to run (pass -D url for the rest)
-#   com.android.chrome/.Main
-#   com.google.android.apps.chrome/.Main
 
 class PossibleAndroidBrowser(possible_browser.PossibleBrowser):
   """A launchable android browser instance."""
@@ -137,6 +132,7 @@ class PossibleAndroidBrowser(possible_browser.PossibleBrowser):
       return os.path.getmtime(self._local_apk)
     return -1
 
+
 def SelectDefaultBrowser(possible_browsers):
   local_builds_by_date = sorted(possible_browsers,
                                 key=lambda b: b.last_modification_time())
@@ -146,41 +142,35 @@ def SelectDefaultBrowser(possible_browsers):
     return newest_browser
   return None
 
-adb_works = None
+
+@decorators.Cache
 def CanFindAvailableBrowsers(logging=real_logging):
   if not adb_commands.IsAndroidSupported():
     logging.info('Android build commands unavailable on this machine. Have '
                  'you installed Android build dependencies?')
     return False
 
-  global adb_works
-
-  if adb_works == None:
-    try:
-      with open(os.devnull, 'w') as devnull:
-        proc = subprocess.Popen(['adb', 'devices'],
-                                stdout=subprocess.PIPE,
-                                stderr=subprocess.PIPE,
-                                stdin=devnull)
-        stdout, _ = proc.communicate()
-        if re.search(re.escape('????????????\tno permissions'), stdout) != None:
-          logging.warn(
-              ('adb devices reported a permissions error. Consider '
-               'restarting adb as root:'))
-          logging.warn('  adb kill-server')
-          logging.warn('  sudo `which adb` devices\n\n')
-        adb_works = True
-    except OSError:
-      platform_tools_path = os.path.join(util.GetChromiumSrcDir(),
-          'third_party', 'android_tools', 'sdk', 'platform-tools')
-      if (sys.platform.startswith('linux') and
-          os.path.exists(os.path.join(platform_tools_path, 'adb'))):
-        os.environ['PATH'] = os.pathsep.join([platform_tools_path,
-                                              os.environ['PATH']])
-        adb_works = True
-      else:
-        adb_works = False
-  return adb_works
+  try:
+    with open(os.devnull, 'w') as devnull:
+      proc = subprocess.Popen(
+          ['adb', 'devices'],
+          stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=devnull)
+      stdout, _ = proc.communicate()
+    if re.search(re.escape('????????????\tno permissions'), stdout) != None:
+      logging.warn('adb devices reported a permissions error. Consider '
+                   'restarting adb as root:')
+      logging.warn('  adb kill-server')
+      logging.warn('  sudo `which adb` devices\n\n')
+    return True
+  except OSError:
+    platform_tools_path = os.path.join(util.GetChromiumSrcDir(),
+        'third_party', 'android_tools', 'sdk', 'platform-tools')
+    if (sys.platform.startswith('linux') and
+        os.path.exists(os.path.join(platform_tools_path, 'adb'))):
+      os.environ['PATH'] = os.pathsep.join([platform_tools_path,
+                                            os.environ['PATH']])
+      return True
+  return False
 
 
 def FindAllAvailableBrowsers(finder_options, logging=real_logging):
diff --git a/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder_unittest.py b/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder_unittest.py
index af26584..de9e72a 100644
--- a/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder_unittest.py
+++ b/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder_unittest.py
@@ -25,7 +25,7 @@ class AndroidBrowserFinderTest(unittest.TestCase):
   def setUp(self):
     self._stubs = system_stub.Override(android_browser_finder,
                                        ['adb_commands', 'os', 'subprocess'])
-    android_browser_finder.adb_works = None  # Blow cache between runs.
+    self._log_stub = LoggingStub()
 
   def tearDown(self):
     self._stubs.Restore()
@@ -36,13 +36,15 @@ class AndroidBrowserFinderTest(unittest.TestCase):
     def NoAdb(*args, **kargs): # pylint: disable=W0613
       raise OSError('not found')
     self._stubs.subprocess.Popen = NoAdb
-    browsers = android_browser_finder.FindAllAvailableBrowsers(finder_options)
+    browsers = android_browser_finder.FindAllAvailableBrowsers(
+        finder_options, self._log_stub)
     self.assertEquals(0, len(browsers))
 
   def test_adb_no_devices(self):
     finder_options = browser_options.BrowserFinderOptions()
 
-    browsers = android_browser_finder.FindAllAvailableBrowsers(finder_options)
+    browsers = android_browser_finder.FindAllAvailableBrowsers(
+        finder_options, self._log_stub)
     self.assertEquals(0, len(browsers))
 
   def test_adb_permissions_error(self):
@@ -55,10 +57,9 @@ class AndroidBrowserFinderTest(unittest.TestCase):
 * daemon started successfully *
 """)
 
-    log_stub = LoggingStub()
     browsers = android_browser_finder.FindAllAvailableBrowsers(
-      finder_options, log_stub)
-    self.assertEquals(3, len(log_stub.warnings))
+        finder_options, self._log_stub)
+    self.assertEquals(3, len(self._log_stub.warnings))
     self.assertEquals(0, len(browsers))
 
   def test_adb_two_devices(self):
@@ -67,10 +68,9 @@ class AndroidBrowserFinderTest(unittest.TestCase):
     self._stubs.adb_commands.attached_devices = ['015d14fec128220c',
                                                  '015d14fec128220d']
 
-    log_stub = LoggingStub()
     browsers = android_browser_finder.FindAllAvailableBrowsers(
-      finder_options, log_stub)
-    self.assertEquals(1, len(log_stub.warnings))
+        finder_options, self._log_stub)
+    self.assertEquals(1, len(self._log_stub.warnings))
     self.assertEquals(0, len(browsers))
 
   @benchmark.Disabled('chromeos')
@@ -88,5 +88,6 @@ class AndroidBrowserFinderTest(unittest.TestCase):
 
     self._stubs.adb_commands.shell_command_handlers['pm'] = OnPM
 
-    browsers = android_browser_finder.FindAllAvailableBrowsers(finder_options)
+    browsers = android_browser_finder.FindAllAvailableBrowsers(
+        finder_options, self._log_stub)
     self.assertEquals(1, len(browsers))