telemetry: handle tests that are not supported on a platform.

tools/telemetry/telemetry/page/page_test_runner.py

Index: tools/telemetry/telemetry/page/page_test_runner.py
diff --git a/tools/telemetry/telemetry/page/page_test_runner.py b/tools/telemetry/telemetry/page/page_test_runner.py
index b594987cceed0be66d39c9050b90fd1e39c3731b..135472335db4a089f6c7fcdd8ecaf882bbc98ec8 100644
--- a/tools/telemetry/telemetry/page/page_test_runner.py
+++ b/tools/telemetry/telemetry/page/page_test_runner.py
@@ -1,15 +1,17 @@
 # Copyright (c) 2012 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 sys
 
 from telemetry import test as test_module
 from telemetry.core import browser_options
 from telemetry.core import discover
-from telemetry.page import page_test as page_test_module
 from telemetry.page import page_runner
 from telemetry.page import page_set
+from telemetry.page import page_test as page_test_module
+from telemetry.page import page_test_results
 
 def Main(base_dir, page_set_filenames):
   """Turns a PageTest into a command-line program.
@@ -37,7 +39,11 @@ class PageTestRunner(object):
   def Run(self, base_dir, page_set_filenames):
     test, ps, expectations = self.ParseCommandLine(sys.argv, base_dir,
         page_set_filenames)
-    results = page_runner.Run(test, ps, expectations, self._options)
+    results = page_test_results.PageTestResults()
+    try:
+      results = page_runner.Run(test, ps, expectations, self._options)
+    except page_test_module.TestNotSupportedOnPlatformFailure as failure:

[dtu, 2013/12/20 19:28:01]

Not here. There's a big exception handling block in page_runner.py that handles
these exceptions. But since TestNotSupportedOnPlatformFailure is a subclass of
Failure, I think it's already handled.

[ernstm, 2013/12/20 23:25:59]

We can't handle the exception in PageRunner, because the unit tests would fail
(it would get an empty result and complain about missing metrics). The
try/except is wrapped around page_runner.Run, because this will get called from
both run_measurement and the unit tests and those want to handle the exception
differently. For run_measuremnt, we want to return an empty results and in the
unit test we just want to return and make the test pass. The exception handling
block in PageRunner only catches the TestNotSupportedOnPlaformFailure and raises
it again so that the caller can handle it.

+      logging.warning(str(failure))
     results.PrintSummary()
     return min(255, len(results.failures + results.errors))