chrome/test/mini_installer/verifier.py

   1 # Copyright 2013 The Chromium 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
   6 class Verifier:
   7   """Verifies that the current machine states match the expectation."""
   8
   9   def VerifyInput(self, verifier_input, variable_expander):
  10     """Verifies that the current machine states match |verifier_input|.
  11
  12     Args:
  13       verifier_input: An input to the verifier. It is a dictionary where each
  14           key is an expectation name and the associated value is an expectation
  15           dictionary. The expectation dictionary may contain an optional
  16           'condition' property, a string that determines whether the expectation
  17           should be verified. Each subclass can specify a different expectation
  18           name and expectation dictionary.
  19       variable_expander: A VariableExpander object.
  20     """
  21     for expectation_name, expectation in verifier_input.iteritems():
  22       if 'condition' in expectation:
  23         condition = variable_expander.Expand(expectation['condition'])
  24         if not self._EvaluateCondition(condition):
  25           continue
  26       self._VerifyExpectation(expectation_name, expectation, variable_expander)
  27
  28   def _VerifyExpectation(self, expectation_name, expectation,
  29                          variable_expander):
  30     """Verifies that the current machine states match |verifier_input|.
  31
  32     This is an abstract method for subclasses to override.
  33
  34     Args:
  35       expectation_name: An expectation name. Each subclass can specify a
  36           different expectation name format.
  37       expectation: An expectation dictionary. Each subclass can specify a
  38           different expectation dictionary format.
  39       variable_expander: A VariableExpander object.
  40     """
  41     raise NotImplementedError()
  42
  43   def _EvaluateCondition(self, condition):
  44     """Evaluates |condition| using eval().
  45
  46     Args:
  47       condition: A condition string.
  48
  49     Returns:
  50       The result of the evaluated condition.
  51     """
  52     return eval(condition, {'__builtins__': None}, None)