# Copyright (c) 2011 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. """Simplify unit tests based on pymox.""" import os import random import shutil import string import StringIO import subprocess import sys sys.path.append(os.path.dirname(os.path.dirname(__file__))) from third_party.pymox import mox class IsOneOf(mox.Comparator): def __init__(self, keys): self._keys = keys def equals(self, rhs): return rhs in self._keys def __repr__(self): return '<sequence or map containing \'%s\'>' % str(self._keys) class TestCaseUtils(object): """Base class with some additional functionalities. People will usually want to use SuperMoxTestBase instead.""" # Backup the separator in case it gets mocked _OS_SEP = os.sep _RANDOM_CHOICE = random.choice _RANDOM_RANDINT = random.randint _STRING_LETTERS = string.letters ## Some utilities for generating arbitrary arguments. def String(self, max_length): return ''.join([self._RANDOM_CHOICE(self._STRING_LETTERS) for _ in xrange(self._RANDOM_RANDINT(1, max_length))]) def Strings(self, max_arg_count, max_arg_length): return [self.String(max_arg_length) for _ in xrange(max_arg_count)] def Args(self, max_arg_count=8, max_arg_length=16): return self.Strings(max_arg_count, self._RANDOM_RANDINT(1, max_arg_length)) def _DirElts(self, max_elt_count=4, max_elt_length=8): return self._OS_SEP.join(self.Strings(max_elt_count, max_elt_length)) def Dir(self, max_elt_count=4, max_elt_length=8): return (self._RANDOM_CHOICE((self._OS_SEP, '')) + self._DirElts(max_elt_count, max_elt_length)) def RootDir(self, max_elt_count=4, max_elt_length=8): return self._OS_SEP + self._DirElts(max_elt_count, max_elt_length) def compareMembers(self, obj, members): """If you add a member, be sure to add the relevant test!""" # Skip over members starting with '_' since they are usually not meant to # be for public use. actual_members = [x for x in sorted(dir(obj)) if not x.startswith('_')] expected_members = sorted(members) if actual_members != expected_members: diff = ([i for i in actual_members if i not in expected_members] + [i for i in expected_members if i not in actual_members]) print >> sys.stderr, diff # pylint: disable=no-member self.assertEqual(actual_members, expected_members) def setUp(self): self.root_dir = self.Dir() self.args = self.Args() self.relpath = self.String(200) def tearDown(self): pass class StdoutCheck(object): def setUp(self): # Override the mock with a StringIO, it's much less painful to test. self._old_stdout = sys.stdout stdout = StringIO.StringIO() stdout.flush = lambda: None sys.stdout = stdout def tearDown(self): try: # If sys.stdout was used, self.checkstdout() must be called. # pylint: disable=no-member if not sys.stdout.closed: self.assertEquals('', sys.stdout.getvalue()) except AttributeError: pass sys.stdout = self._old_stdout def checkstdout(self, expected): value = sys.stdout.getvalue() sys.stdout.close() # pylint: disable=no-member self.assertEquals(expected, value) class SuperMoxTestBase(TestCaseUtils, StdoutCheck, mox.MoxTestBase): def setUp(self): """Patch a few functions with know side-effects.""" TestCaseUtils.setUp(self) mox.MoxTestBase.setUp(self) os_to_mock = ('chdir', 'chown', 'close', 'closerange', 'dup', 'dup2', 'fchdir', 'fchmod', 'fchown', 'fdopen', 'getcwd', 'listdir', 'lseek', 'makedirs', 'mkdir', 'open', 'popen', 'popen2', 'popen3', 'popen4', 'read', 'remove', 'removedirs', 'rename', 'renames', 'rmdir', 'symlink', 'system', 'tmpfile', 'walk', 'write') self.MockList(os, os_to_mock) os_path_to_mock = ('abspath', 'exists', 'getsize', 'isdir', 'isfile', 'islink', 'ismount', 'lexists', 'realpath', 'samefile', 'walk') self.MockList(os.path, os_path_to_mock) self.MockList(shutil, ('rmtree')) self.MockList(subprocess, ('call', 'Popen')) # Don't mock stderr since it confuses unittests. self.MockList(sys, ('stdin')) StdoutCheck.setUp(self) def tearDown(self): StdoutCheck.tearDown(self) TestCaseUtils.tearDown(self) mox.MoxTestBase.tearDown(self) def MockList(self, parent, items_to_mock): for item in items_to_mock: # Skip over items not present because of OS-specific implementation, # implemented only in later python version, etc. if hasattr(parent, item): try: self.mox.StubOutWithMock(parent, item) except TypeError, e: raise TypeError( 'Couldn\'t mock %s in %s: %s' % (item, parent.__name__, e)) def UnMock(self, obj, name): """Restore an object inside a test.""" for (parent, old_child, child_name) in self.mox.stubs.cache: if parent == obj and child_name == name: setattr(parent, child_name, old_child) break