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      1 # Copyright 2017 The Chromium OS Authors. All rights reserved.
      2 # Use of this source code is governed by a BSD-style license that can be
      3 # found in the LICENSE file.
      4 
      5 import glob
      6 import logging
      7 import os
      8 import utils
      9 
     10 from autotest_lib.client.common_lib import error
     11 from autotest_lib.client.cros.enterprise import enterprise_policy_base
     12 from autotest_lib.client.cros.input_playback import input_playback
     13 
     14 POLL_TIMEOUT = 5
     15 POLL_FREQUENCY = 0.5
     16 
     17 
     18 class policy_DisableScreenshots(
     19         enterprise_policy_base.EnterprisePolicyTest):
     20     """
     21     Test DisableScreenshots policy effect on ChromerOS behavior.
     22 
     23     This test verifies the behavior of Chrome OS with a set of valid values
     24     for the DisableScreenshots user policy ie, the policy value is set to True,
     25     False or is Unset.
     26     These valid values are covered by the test cases: DisableScreenshot_Block,
     27     NotSet_Allow and False_Allow.
     28 
     29     When the policy value is None or is set to False (as in the cases
     30     NotSet_Allow and False_Allow), then screenshots will be captured on pressing
     31     the Ctrl and F5 keyboard buttons. When the value is set to True (as in case
     32     DisableScreenshot_Block), screenshot capture is disabled.
     33 
     34     """
     35     version = 1
     36 
     37     def initialize(self, **kwargs):
     38         """Emulate a keyboard in order to play back the screenshot shortcut."""
     39         self._initialize_test_constants()
     40         super(policy_DisableScreenshots, self).initialize(**kwargs)
     41         self.player = input_playback.InputPlayback()
     42         self.player.emulate(input_type='keyboard')
     43         self.player.find_connected_inputs()
     44 
     45 
     46     def _initialize_test_constants(self):
     47         """Initialize test-specific constants, some from class constants."""
     48         self.POLICY_NAME = 'DisableScreenshots'
     49         self._DOWNLOADS = '/home/chronos/user/Downloads/'
     50         self._SCREENSHOT_PATTERN = 'Screenshot*'
     51         self._SCREENSHOT_FILENAME = self._DOWNLOADS + self._SCREENSHOT_PATTERN
     52 
     53         self.TEST_CASES = {
     54             'DisableScreenshot_Block': True,
     55             'False_Allow': False,
     56             'NotSet_Allow': None
     57         }
     58         self.STARTUP_URLS = ['chrome://policy', 'chrome://settings']
     59         self.SUPPORTING_POLICIES = {
     60             'RestoreOnStartupURLs': self.STARTUP_URLS,
     61             'RestoreOnStartup': 4
     62         }
     63 
     64 
     65     def _capture_screenshot(self):
     66         """Capture a screenshot by pressing Ctrl +F5."""
     67         self.player.blocking_playback_of_default_file(
     68                 input_type='keyboard', filename='keyboard_ctrl+f5')
     69 
     70 
     71     def _screenshot_file_exists(self):
     72         """
     73         Return True if screenshot was captured. else returns False.
     74 
     75         @returns boolean indicating if screenshot file was saved or not.
     76 
     77         """
     78         try:
     79             utils.poll_for_condition(
     80                     lambda: len(glob.glob(self._SCREENSHOT_FILENAME)) > 0,
     81                     timeout=POLL_TIMEOUT,
     82                     sleep_interval=POLL_FREQUENCY)
     83         except utils.TimeoutError:
     84             logging.info('Screenshot file not found.')
     85             return False
     86 
     87         logging.info('Screenshot file found.')
     88         return True
     89 
     90 
     91     def _delete_screenshot_files(self):
     92         """Delete existing screenshot files, if any."""
     93         for filename in glob.glob(self._SCREENSHOT_FILENAME):
     94             os.remove(filename)
     95 
     96 
     97     def cleanup(self):
     98         """Cleanup files created in this test, if any and close the player."""
     99         self._delete_screenshot_files()
    100         self.player.close()
    101         super(policy_DisableScreenshots, self).cleanup()
    102 
    103 
    104     def _test_screenshot_disabled(self, policy_value):
    105         """
    106         Verify CrOS enforces the DisableScreenshots policy.
    107 
    108         When DisableScreenshots policy value is undefined, screenshots shall
    109         be captured via the keyboard shortcut Ctrl + F5.
    110         When DisableScreenshots policy is set to True screenshots shall not
    111         be captured.
    112 
    113         @param policy_value: policy value for this case.
    114 
    115         """
    116         logging.info('Deleting preexisting Screenshot files.')
    117         self._delete_screenshot_files()
    118 
    119         self._capture_screenshot()
    120         screenshot_file_captured = self._screenshot_file_exists()
    121         if policy_value:
    122             if screenshot_file_captured:
    123                 raise error.TestFail('Screenshot should not be captured')
    124         elif not screenshot_file_captured:
    125             raise error.TestFail('Screenshot should be captured')
    126 
    127 
    128     def run_once(self, case):
    129         """
    130         Setup and run the test configured for the specified test case.
    131 
    132         @param case: Name of the test case to run.
    133 
    134         """
    135         case_value = self.TEST_CASES[case]
    136         self.SUPPORTING_POLICIES[self.POLICY_NAME] = case_value
    137         self.setup_case(user_policies=self.SUPPORTING_POLICIES)
    138         self._test_screenshot_disabled(case_value)
    139