Obtain confidence score based off last known good and first known bad revision results.

tools/auto_bisect/bisect_results_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 unittest
 
 from bisect_results import BisectResults
 import source_control
 
@@ skipping 209 matching lines @@
     self.assertEqual(1, len(results.warnings))
 
   def testWarningForTooLowRetryLimit(self):
     self.mock_opts.repeat_test_count = 1
     results = BisectResults(self.mock_bisect_state, self.mock_depot_registry,
                             self.mock_opts, self.mock_warnings)
     self.assertEqual(1, len(results.warnings))
 
   def testWarningForTooLowConfidence(self):
     revision_states = self.mock_bisect_state.mock_revision_states
-    revision_states[2].value = {'values': [95, 100, 90]}
-    revision_states[3].value = {'values': [95, 100, 90]}
-    revision_states[4].value = {'values': [95, 100, 90]}
+    revision_states[2].value = {'values': [95, 90, 90]}

[RobertoCN, 2015/01/14 18:50:47]

Because of the new way of obtaining the confidence, needed to alter this test so
it would yield a confidence greater than 0, but yielding a warning.

[RobertoCN, 2015/01/30 21:23:32]

Done.

+    revision_states[3].value = {'values': [95, 90, 90]}
+    revision_states[4].value = {'values': [95, 90, 90]}
     results = BisectResults(self.mock_bisect_state, self.mock_depot_registry,
                             self.mock_opts, self.mock_warnings)
     self.assertGreater(results.confidence, 0)
     self.assertEqual(1, len(results.warnings))
 
   def testWarningForZeroConfidence(self):
     revision_states = self.mock_bisect_state.mock_revision_states
     revision_states[2].value = {'values': [100, 105, 95]}
     revision_states[3].value = {'values': [100, 105, 95]}
     revision_states[4].value = {'values': [100, 105, 95]}
     results = BisectResults(self.mock_bisect_state, self.mock_depot_registry,
                             self.mock_opts, self.mock_warnings)
     self.assertEqual(0, results.confidence)
     self.assertEqual(1, len(results.warnings))
 
 
 if __name__ == '__main__':
   unittest.main()