CrOS: Use local Chromite checkout for configs.

scripts/slave/recipe_modules/chromite/example.py

 # Copyright 2013 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.
 
 DEPS = [
   'chromite',
+  'gitiles',
 ]
 
 
+_TEST_CONFIG = {
+  '_default': {
+    'foo': 'bar',
+    'baz': 'qux',
+  },
+  '_templates': {
+    'woot': {
+      'baz': 'templated',
+    }
+  },
+  'myconfig': {
+    '_template': 'woot',
+    'local': 'variable',
+  },
+}
+
 def RunSteps(api):
   api.chromite.set_config('base')
 
   # Basic checkout exercise.
   api.chromite.checkout()
   api.chromite.setup_board('amd64-generic', args=['--cache-dir', '.cache'])
   api.chromite.build_packages('amd64-generic')
   api.chromite.cros_sdk('cros_sdk', ['echo', 'hello'],
                         environ={ 'var1': 'value' })
   api.chromite.cbuildbot('cbuildbot', 'amd64-generic-full',
                          args=['--clobber', '--build-dir', '/here/there'])
 
+  # Exercise valid configuraiton.
+  config = api.chromite.load_config('myconfig')
+  assert config is not None
+  assert config['foo'] == 'bar'
+  assert config['baz'] == 'templated'
+  assert config['local'] == 'variable'
+  assert config.get('invalid') is None
+
+  raised = False
+  try:
+    config['invalid']
+  except KeyError:
+    raised = True
+  assert raised, 'Did not raise KeyError!'
+
+  # Exercise invalid configuration.
+  assert api.chromite.load_config('nonexistent') is None
+
 
 def GenTests(api):
-  yield api.test('basic')
+  yield (api.test('basic') +
+      api.chromite.seed_chromite_config(_TEST_CONFIG)
+  )
+