Refactored bisect results dicts into a separate class

tools/auto_bisect/bisect_perf_regression_test.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 os
 import re
 import unittest
 
 import bisect_perf_regression
 import source_control as source_control_module
@@ skipping 14 matching lines @@
   source_control = source_control_module.DetermineAndCreateSourceControl(
       bisect_options)
   bisect_instance = bisect_perf_regression.BisectPerformanceMetrics(
       source_control, bisect_options)
   return bisect_instance
 
 
 class BisectPerfRegressionTest(unittest.TestCase):
   """Test case for other functions and classes in bisect-perf-regression.py."""
 
+  def setUp(self):
+    self.cwd = os.getcwd()
+
+  def tearDown(self):
+    os.chdir(self.cwd)
+
   def _AssertConfidence(self, score, bad_values, good_values):
     """Checks whether the given sets of values have a given confidence score.
 
     The score represents our confidence that the two sets of values wouldn't
     be as different as they are just by chance; that is, that some real change
     occurred between the two sets of values.
 
     Args:
       score: Expected confidence score.
       bad_values: First list of numbers.
@@ skipping 230 matching lines @@
     bisect_instance = _GetBisectPerformanceMetricsInstance()
     wk_rev = 'a94d028e0f2c77f159b3dac95eb90c3b4cf48c61'
     depot_path = os.path.join(bisect_perf_regression.SRC_DIR, 'third_party',
                               'WebKit')
     self.assertEqual(
         181660,
         bisect_instance.source_control.GetCommitPosition(wk_rev, depot_path))
 
   def testUpdateDepsContent(self):
     bisect_instance = _GetBisectPerformanceMetricsInstance()
-    deps_file = 'DEPS'
+    deps_file = os.path.join(bisect_perf_regression.SRC_DIR, 'DEPS')
     # We are intentionally reading DEPS file contents instead of string literal
     # with few lines from DEPS because to check if the format we are expecting
     # to search is not changed in DEPS content.
     # TODO (prasadv): Add a separate test to validate the DEPS contents with the
     # format that bisect script expects.
     deps_contents = bisect_perf_regression.ReadStringFromFile(deps_file)
     deps_key = 'v8_revision'
     depot = 'v8'
     git_revision = 'a12345789a23456789a123456789a123456789'
     updated_content = bisect_instance.UpdateDepsContents(
         deps_contents, depot, git_revision, deps_key)
     self.assertIsNotNone(updated_content)
     ss = re.compile('["\']%s["\']: ["\']%s["\']' % (deps_key, git_revision))
     self.assertIsNotNone(re.search(ss, updated_content))
 
 
 if __name__ == '__main__':
   unittest.main()