Replace recipes_test.py with a new parallel expectation-based test runner.

scripts/slave/unittests/expect_tests/serialize.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 difflib
+import json
+import os
+import pprint
+
+try:
+  import yaml  # pylint: disable=F0401
+except ImportError:
+  yaml = None
+
+
+NonExistant = object()
+
+
+SUPPORTED_SERIALIZERS = {'json', 'yaml'}
+SERIALIZERS = {}
+
+
+# JSON support
+def re_encode(obj):
+  if isinstance(obj, dict):
+    return {re_encode(k): re_encode(v) for k, v in obj.iteritems()}
+  elif isinstance(obj, list):
+    return [re_encode(i) for i in obj]
+  elif isinstance(obj, unicode):
+    return obj.encode('utf-8')
+  else:
+    return obj
+
+
+SERIALIZERS['json'] = (
+    lambda s: re_encode(json.load(s)),
+    lambda data, stream: json.dump(
+        data, stream, sort_keys=True, indent=2, separators=(',', ': ')))
+
+
+# YAML support
+if yaml:
+  _YAMLSafeLoader = getattr(yaml, 'CSafeLoader', yaml.SafeLoader)
+  _YAMLSafeDumper = getattr(yaml, 'CSafeDumper', yaml.SafeDumper)
+  SERIALIZERS['yaml'] = (
+      lambda stream: yaml.load(stream, _YAMLSafeLoader),
+      lambda data, stream: yaml.dump(
+          data, stream, _YAMLSafeDumper, default_flow_style=False,
+          encoding='utf-8'))
+
+
+def GetCurrentData(test):
+  """
+  @type test: Test()
+  @returns: The deserialized data (or NonExistant), and a boolean indicating if
+            the current serialized data is in the same format which was
+            requested by |test|.
+  @rtype: (dict, bool)
+  """
+  for ext in sorted(SUPPORTED_SERIALIZERS, key=lambda s: s != test.ext):
+    path = test.expect_path(ext)
+    if ext not in SERIALIZERS:
+      raise Exception('The package to support %s is not installed.' % ext)
+    if os.path.exists(path):
+      with open(path, 'rb') as f:
+        data = SERIALIZERS[ext][0](f)
+      return data, ext == test.ext
+  return NonExistant, True
+
+
+def WriteNewData(test, data):
+  """
+  @type test: Test()
+  """
+  if test.ext not in SUPPORTED_SERIALIZERS:
+    raise Exception('%s is not a supported serializer.' % test.ext)
+  if test.ext not in SERIALIZERS:
+    raise Exception('The package to support %s is not installed.' % test.ext)
+  with open(test.expect_path(), 'wb') as f:
+    SERIALIZERS[test.ext][1](data, f)
+
+
+def DiffData(old, new):
+  """
+  Takes old data and new data, then returns a textual diff as a list of lines.
+  @type old: dict
+  @type new: dict
+  @rtype: [str]
+  """
+  if old is NonExistant:
+    return new
+  if old == new:
+    return None
+  else:
+    return list(difflib.context_diff(
+        pprint.pformat(old).splitlines(),
+        pprint.pformat(new).splitlines(),
+        fromfile='expected', tofile='current',
+        n=4, lineterm=''
+    ))