[telemetry] Prototype for specifying page sets using Python imports and Telemetry discovery.

tools/perf/page_sets/page_set_unittest.py

 # Copyright 2014 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 unittest
 
 from telemetry.core import discover
-from telemetry.page import page_set as page_set_module
+from telemetry.page import page_set
 from telemetry.page import page_set_archive_info
 
 
 class PageSetUnitTest(unittest.TestCase):
 
   def testSmoke(self):
     # Instantiate all page sets and verify that all URLs have an associated
     # archive.
-    page_sets_dir = os.path.dirname(__file__)
-    page_sets = discover.GetAllPageSetFilenames(page_sets_dir)
-    for path in page_sets:
-      page_set = page_set_module.PageSet.FromFile(path)
+    page_sets_dir = os.path.dirname(os.path.realpath(__file__))
+    top_level_dir = os.path.dirname(page_sets_dir)
+    page_sets = discover.DiscoverClasses(
+        page_sets_dir, top_level_dir, page_set.PageSet).values()
+    for page_set_class in page_sets:
+      page_set_file = page_set_class.__module__
+      ps = page_set_class()
 
       # TODO: Eventually these should be fatal.
-      if not page_set.archive_data_file:
-        logging.warning('Skipping %s: missing archive data file', path)
+      if not ps.archive_data_file:
+        logging.warning('Skipping %s: missing archive data file', page_set_file)
         continue
-      if not os.path.exists(os.path.join(page_sets_dir,
-                                         page_set.archive_data_file)):
-        logging.warning('Skipping %s: archive data file not found', path)
+      if not os.path.exists(os.path.join(page_sets_dir, ps.archive_data_file)):
+        logging.warning('Skipping %s: archive data file not found',
+                        page_set_file)
         continue
 
       wpr_archive_info = page_set_archive_info.PageSetArchiveInfo.FromFile(
-        os.path.join(page_sets_dir, page_set.archive_data_file),
-        ignore_archive=True)
+          os.path.join(page_sets_dir, ps.archive_data_file),
+          ignore_archive=True)
 
-      logging.info('Testing %s', path)
-      for page in page_set.pages:
+      logging.info('Testing %s', page_set_file)
+      for page in ps.pages:
         if not page.url.startswith('http'):
           continue
         self.assertTrue(wpr_archive_info.WprFilePathForPage(page),
                         msg='No archive found for %s in %s' % (
-                            page.url, page_set.archive_data_file))
+                            page.url, ps.archive_data_file))