Added unittests for run_slave

PRESUBMIT.py

 # 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.
 
 """Top-level presubmit script for buildbot.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts for
 details on the presubmit API built into git cl.
 """
 
 import contextlib
+import os
 import re
 import sys
 
 
 @contextlib.contextmanager
 def pythonpath(path):
   orig = sys.path
   try:
     sys.path = path
     yield
@@ skipping 98 matching lines @@
 
   recipe_modules_tests = input_api.glob(
       join('scripts', 'slave', 'recipe_modules', '*', 'tests'))
   for path in recipe_modules_tests:
     tests.extend(input_api.canned_checks.GetUnitTestsInDirectory(
         input_api,
         output_api,
         path,
         whitelist))
 
+  tests.extend(input_api.canned_checks.GetUnitTestsInDirectory(
+      input_api,
+      output_api,
+      input_api.os_path.join('slave', 'tests'),
+      whitelist,
+      env={'PYTHONPATH': os.pathsep.join(infra_path)}))
+
   with pythonpath(infra_path + sys.path):
     import common.master_cfg_utils  # pylint: disable=F0401
     # Fetch recipe dependencies once in serial so that we don't hit a race
     # condition where multiple tests are trying to fetch at once.
     output = input_api.RunTests([input_api.Command(
         name='recipes fetch',
         cmd=[input_api.python_executable,
              input_api.os_path.join('scripts', 'slave', 'recipes.py'), 'fetch'],
         kwargs={},
         message=output_api.PresubmitError,
@@ skipping 47 matching lines @@
 
 def CheckChangeOnUpload(_input_api, _output_api):
   return [] # Try-jobs/commit-queue do a better job of testing, faster.
 
 
 def CheckChangeOnCommit(input_api, output_api):
   output = CommonChecks(input_api, output_api)
   output.extend(ConditionalChecks(input_api, output_api))
   output.extend(BuildInternalCheck(output, input_api, output_api))
   return output