Refactor infra git libs and testing.

infra/services/gnumbd/test/config_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.
-
-from infra.services.gnumbd.support import config_ref, git
-from infra.services.gnumbd.test import git_test
-
-class TestConfigRef(git_test.TestBasis):
-  def writeConfig(self, config_data):
-    ref = 'refs/metaconfig'
-    def inner():
-      g = self.repo.git
-      if g('rev-parse', ref).stdout.strip() != ref:
-        g('checkout', ref)
-      else:
-        g('checkout', '--orphan', 'config')
-      g('rm', '-rf', '.')
-      with open('config.json', 'w') as f:
-        f.write(config_data)
-      g('add', 'config.json')
-      self.repo.git_commit('a bad config file')
-      g('update-ref', ref, 'HEAD')
-    self.repo.run(inner)
-
-  def testNonExist(self):
-    r = self.mkRepo()
-    c = config_ref.ConfigRef(git.Ref(r, 'refs/metaconfig'))
-    self.assertEqual(c.current, c.DEFAULTS)
-    self.assertEqual(c['interval'], c.DEFAULTS['interval'])
-
-  def testExistsBad(self):
-    self.writeConfig("not valid config")
-    r = self.mkRepo()
-    c = config_ref.ConfigRef(git.Ref(r, 'refs/metaconfig'))
-    c.evaluate()
-    self.assertEqual(c.current, c.DEFAULTS)
-
-    self.writeConfig("[]")
-    self.capture_stdio(r.run, 'fetch')
-    c.evaluate()
-    self.assertEqual(c.current, c.DEFAULTS)
-
-  def testExistsGood(self):
-    self.writeConfig('{"interval": 100}')
-    r = self.mkRepo()
-    c = config_ref.ConfigRef(git.Ref(r, 'refs/metaconfig'))
-    self.assertAlmostEqual(c['interval'], 100.0)
-
-    self.writeConfig('{"interval": "cat"}')
-    self.capture_stdio(r.run, 'fetch')
-    c.evaluate()
-    self.assertAlmostEqual(c['interval'], 100.0)