catapult/telemetry/telemetry/story/story.py

# 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 re

from telemetry.story import shared_state as shared_state_module

_next_story_id = 0


class Story(object):
  """A class styled on unittest.TestCase for creating story tests.

  Tests should override Run to maybe start the application and perform actions
  on it. To share state between different tests, one can define a
  shared_state which contains hooks that will be called before and
  after mutiple stories run and in between runs.

  Args:
    shared_state_class: subclass of telemetry.story.shared_state.SharedState.
    name: string name of this story that can be used for identifying this story
        in results output.
    labels: A list or set of string labels that are used for filtering. See
        story.story_filter for more information.
    is_local: If True, the story does not require network.
  """

  def __init__(self, shared_state_class, name='', labels=None,
               is_local=False, make_javascript_deterministic=True):
    """
    Args:
      make_javascript_deterministic: Whether JavaScript performed on
          the page is made deterministic across multiple runs. This
          requires that the web content is served via Web Page Replay
          to take effect. This setting does not affect stories containing no web
          content or where the HTTP MIME type is not text/html.See also:
          _InjectScripts method in third_party/webpagereplay/httpclient.py.
    """
    assert issubclass(shared_state_class,
                      shared_state_module.SharedState)
    self._shared_state_class = shared_state_class
    self._name = name
    global _next_story_id
    self._id = _next_story_id
    _next_story_id += 1
    if labels is None:
      labels = set([])
    elif isinstance(labels, list):
      labels = set(labels)
    else:
      assert isinstance(labels, set)
    self._labels = labels
    self._is_local = is_local
    self._make_javascript_deterministic = make_javascript_deterministic

  def Run(self, shared_state):
    """Execute the interactions with the applications and/or platforms."""
    raise NotImplementedError

  @property
  def labels(self):
    return self._labels

  @property
  def shared_state_class(self):
    return self._shared_state_class

  @property
  def id(self):
    return self._id

  @property
  def name(self):
    return self._name

  def AsDict(self):
    """Converts a story object to a dict suitable for JSON output."""
    d = {
      'id': self._id,
    }
    if self._name:
      d['name'] = self._name
    return d

  @property
  def file_safe_name(self):
    """A version of display_name that's safe to use as a filename.

    The default implementation sanitizes special characters with underscores,
    but it's okay to override it with a more specific implementation in
    subclasses.
    """
    # This fail-safe implementation is safe for subclasses to override.
    return re.sub('[^a-zA-Z0-9]', '_', self.display_name)

  @property
  def display_name(self):
    if self.name:
      return self.name
    else:
      return self.__class__.__name__

  @property
  def is_local(self):
    """Returns True iff this story does not require network."""
    return self._is_local

  @property
  def serving_dir(self):
    """Returns the absolute path to a directory with hash files to data that
       should be updated from cloud storage, or None if no files need to be
       updated.
    """
    return None

  @property
  def make_javascript_deterministic(self):
    return self._make_javascript_deterministic