Making check_initial_confidence verify return_code bisects.

scripts/slave/recipe_modules/auto_bisect/bisector_test.py

 #!/usr/bin/env python
 # Copyright 2015 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 copy
 import os
 import sys
 import unittest
 
@@ skipping 13 matching lines @@
   def __init__(
       self, bisector, commit_hash,
       depot_name='chromium', base_revision=None):
     self.bisector = bisector
     self.commit_hash = commit_hash
     self.depot_name = depot_name
     self.base_revision = base_revision
     self.previous_revision = None
     self.next_revision = None
     self.values = []
+    self.overall_return_code = None
     self.deps = {}
     self.status = ''
 
   def read_deps(self, tester_name):
     pass
 
   def retest(self):
     self.bisector.last_tested_revision = self
     self.values.append(3)
 
@@ skipping 96 matching lines @@
     bisector = auto_bisect.bisector.Bisector(self.dummy_api, self.bisect_config,
                                              MockRevisionClass)
     bisector.good_rev.values = [3, 3, 3, 3, 3, 3]
     bisector.bad_rev.values = [3, 3, 3, 3]
     self.assertFalse(bisector.check_initial_confidence())
     self.assertTrue(len(bisector.bad_rev.values) >=
                     auto_bisect.bisector.MAX_REQUIRED_SAMPLES or
                     len(bisector.good_rev.values) >=
                     auto_bisect.bisector.MAX_REQUIRED_SAMPLES)
 
-  @mock.patch.object(auto_bisect.bisector.Bisector, 'significantly_different',
-                     mock.MagicMock())
-  def test_check_initial_confidence_not_required(self):
+  def test_check_initial_confidence_return_code_pass(self):
     return_code_config = self.bisect_config
     return_code_config['test_type'] = 'return_code'
-    # When confidence is not required, confidence_score should not be called.
     bisector = auto_bisect.bisector.Bisector(self.dummy_api, return_code_config,
                                              MockRevisionClass)
+    bisector.good_rev.overall_return_code = 0
+    bisector.bad_rev.overall_return_code = 1
     self.assertTrue(bisector.check_initial_confidence())
-    self.assertFalse(bisector.significantly_different.called)
+
+  def test_check_initial_confidence_return_code_fail(self):
+    return_code_config = self.bisect_config
+    return_code_config['test_type'] = 'return_code'
+    bisector = auto_bisect.bisector.Bisector(self.dummy_api, return_code_config,
+                                             MockRevisionClass)
+    bisector.good_rev.overall_return_code = 0
+    bisector.bad_rev.overall_return_code = 0
+    self.assertFalse(bisector.check_initial_confidence())
+
+    bisector.good_rev.overall_return_code = 1
+    bisector.bad_rev.overall_return_code = 1
+    self.assertFalse(bisector.check_initial_confidence())
 
 
 if __name__ == '__main__':
   unittest.main()  # pragma: no cover