[I-Spy] Add utilities to help manage expectations that track Chrome versions.

chrome/test/functional/ispy/client/chrome_utils.py

+# Copyright (c) 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.
+
+import json
+import logging
+import os
+import time
+from distutils.version import LooseVersion
+from PIL import Image
+
+from ..common import cloud_bucket
+from ..common import ispy_utils
+
+
+class ChromeUtils(object):
+  """A utility for using ISpy with Chrome."""
+
+  def __init__(self, cloud_bucket, version_file, screenshot_func):
+    """Initializes the utility class.
+
+    Args:
+      cloud_bucket: a BaseCloudBucket in which to the version file,
+          expectations and results are to be stored.
+      version_file: path to the version file in the cloud bucket. The version
+          file contains a json list of ordered Chrome versions for which
+          expectations exist.
+      screenshot_func: a function that returns a PIL.Image.
+    """
+    self._cloud_bucket = cloud_bucket
+    self._version_file = version_file
+    self._screenshot_func = screenshot_func
+    self._ispy = ispy_utils.ISpyUtils(self._cloud_bucket)
+    with open(
+        os.path.join(os.path.dirname(__file__), 'wait_on_ajax.js'), 'r') as f:
+      self._wait_for_unchanging_dom_script = f.read()
+
+  def UpdateExpectationVersion(self, chrome_version):
+    """Updates the most recent expectation version to the Chrome version.
+
+    Should be called after generating a new set of expectations.
+
+    Args:
+      chrome_version: the chrome version as a string of the form "31.0.123.4".
+    """
+    insert_pos = 0
+    expectation_versions = []
+    try:
+      expectation_versions = self._GetExpectationVersionList()
+      if expectation_versions:
+        try:
+          version = self._GetExpectationVersion(
+              chrome_version, expectation_versions)
+          if version == chrome_version:
+            return
+          insert_pos = expectation_versions.index(version)
+        except:
+          insert_pos = len(expectation_versions)
+    except cloud_bucket.FileNotFoundError:
+      pass
+    expectation_versions.insert(insert_pos, chrome_version)
+    logging.info('Updating expectation version...')
+    self._cloud_bucket.UploadFile(
+        self._version_file, json.dumps(expectation_versions),
+        'application/json')
+
+  def _GetExpectationVersion(self, chrome_version, expectation_versions):
+    """Returns the expectation version for the given Chrome version.
+
+    Args:
+      chrome_version: the chrome version as a string of the form "31.0.123.4".
+      expectation_versions: Ordered list of Chrome versions for which
+        expectations exist, as stored in the version file.
+
+    Returns:
+      Expectation version string.
+    """
+    # Find the closest version that is not greater than the chrome version.
+    for version in expectation_versions:
+      if LooseVersion(version) <= LooseVersion(chrome_version):
+        return version
+    raise Exception('No expectation exists for Chrome %s' % chrome_version)
+
+  def _GetExpectationVersionList(self):
+    """Gets the list of expectation versions from google storage."""
+    return json.loads(self._cloud_bucket.DownloadFile(self._version_file))
+
+  def _GetExpectationNameWithVersion(self, device_type, expectation,
+                                     chrome_version):
+    """Get the expectation to be used with the current Chrome version.
+
+    Args:
+      device_type: string identifier for the device type.
+      expectation: name for the expectation to generate.
+      chrome_version: the chrome version as a string of the form "31.0.123.4".
+
+    Returns:
+      Version as an integer.
+    """
+    version = self._GetExpectationVersion(
+        chrome_version, self._GetExpectationVersionList())
+    return self._CreateExpectationName(device_type, expectation, version)
+
+  def _CreateExpectationName(self, device_type, expectation, version):
+    """Create the full expectation name from the expectation and version.

[frankf, 2013/11/06 23:47:26]

Provide examples for all args and return value

[craigdh, 2013/11/07 00:06:16]

Done.

+
+    Args:
+      device_type: string identifier for the device type.
+      expectation: name for the expectation to generate.
+      version: expectation version.
+
+    Returns:
+      Full expectation name as a string.
+    """
+    return '%s:%s(%s)' % (device_type, expectation, version)
+
+  def GenerateExpectation(self, device_type, expectation, chrome_version):
+    """Take screenshots and store as an expectation in I-Spy.
+
+    Args:
+      device_type: string identifier for the device type.
+      expectation: name for the expectation to generate.
+      chrome_version: the chrome version as a string of the form "31.0.123.4".
+    """
+    # https://code.google.com/p/chromedriver/issues/detail?id=463
+    time.sleep(1)
+    expectation_with_version = self._CreateExpectationName(
+        device_type, expectation, chrome_version)
+    if self._ispy.ExpectationExists(expectation_with_version):
+      logging.warning(
+          'I-Spy expectation \'%s\' already exists, overwriting.',
+          expectation_with_version)
+    screenshots = [self._screenshot_func() for _ in range(8)]
+    logging.info('Generating I-Spy expectation...')
+    self._ispy.GenerateExpectation(expectation_with_version, screenshots)
+
+  def PerformComparison(self, test_run, device_type, expectation,
+                        chrome_version):
+    """Take a screenshot and compare it with the given expectation in I-Spy.
+
+    Args:
+      test_run: name for the test run.
+      device_type: string identifier for the device type.
+      expectation: name for the expectation to compare against.
+      chrome_version: the chrome version as a string of the form "31.0.123.4".
+    """
+    # https://code.google.com/p/chromedriver/issues/detail?id=463
+    time.sleep(1)
+    screenshot = self._screenshot_func()
+    logging.info('Performing I-Spy comparison...')
+    self._ispy.PerformComparison(
+        test_run,
+        self._GetExpectationNameWithVersion(
+            device_type, expectation, chrome_version),
+        screenshot)
+
+  def WaitForUnchangingDOM(self, driver):
+    """Waits for the DOM to stop changing.
+
+    Args:
+      driver: a chromedriver driver instance.
+    """
+    try:
+      driver.execute_async_script(self._wait_for_unchanging_dom_script)
+    except exceptions.TimeoutException:
+      logging.warning('Timed out waiting for DOM to stop changing')
+