path: root/cloudinit/tests/helpers.py

# This file is part of cloud-init. See LICENSE file for license information.

from __future__ import print_function

import functools
import logging
import os
import shutil
import sys
import tempfile
import unittest

import mock
import six
import unittest2

try:
    from contextlib import ExitStack
except ImportError:
    from contextlib2 import ExitStack

try:
    from configparser import ConfigParser
except ImportError:
    from ConfigParser import ConfigParser

from cloudinit import helpers as ch
from cloudinit import util

# Used for skipping tests
SkipTest = unittest2.SkipTest

# Used for detecting different python versions
PY2 = False
PY26 = False
PY27 = False
PY3 = False

_PY_VER = sys.version_info
_PY_MAJOR, _PY_MINOR, _PY_MICRO = _PY_VER[0:3]
if (_PY_MAJOR, _PY_MINOR) <= (2, 6):
    if (_PY_MAJOR, _PY_MINOR) == (2, 6):
        PY26 = True
    if (_PY_MAJOR, _PY_MINOR) >= (2, 0):
        PY2 = True
else:
    if (_PY_MAJOR, _PY_MINOR) == (2, 7):
        PY27 = True
        PY2 = True
    if (_PY_MAJOR, _PY_MINOR) >= (3, 0):
        PY3 = True


# Makes the old path start
# with new base instead of whatever
# it previously had
def rebase_path(old_path, new_base):
    if old_path.startswith(new_base):
        # Already handled...
        return old_path
    # Retarget the base of that path
    # to the new base instead of the
    # old one...
    path = os.path.join(new_base, old_path.lstrip("/"))
    path = os.path.abspath(path)
    return path


# Can work on anything that takes a path as arguments
def retarget_many_wrapper(new_base, am, old_func):
    def wrapper(*args, **kwds):
        n_args = list(args)
        nam = am
        if am == -1:
            nam = len(n_args)
        for i in range(0, nam):
            path = args[i]
            # patchOS() wraps various os and os.path functions, however in
            # Python 3 some of these now accept file-descriptors (integers).
            # That breaks rebase_path() so in lieu of a better solution, just
            # don't rebase if we get a fd.
            if isinstance(path, six.string_types):
                n_args[i] = rebase_path(path, new_base)
        return old_func(*n_args, **kwds)
    return wrapper


class TestCase(unittest2.TestCase):

    def reset_global_state(self):
        """Reset any global state to its original settings.

        cloudinit caches some values in cloudinit.util.  Unit tests that
        involved those cached paths were then subject to failure if the order
        of invocation changed (LP: #1703697).

        This function resets any of these global state variables to their
        initial state.

        In the future this should really be done with some registry that
        can then be cleaned in a more obvious way.
        """
        util.PROC_CMDLINE = None
        util._DNS_REDIRECT_IP = None
        util._LSB_RELEASE = {}

    def setUp(self):
        super(TestCase, self).setUp()
        self.reset_global_state()

    def add_patch(self, target, attr, **kwargs):
        """Patches specified target object and sets it as attr on test
        instance also schedules cleanup"""
        if 'autospec' not in kwargs:
            kwargs['autospec'] = True
        m = mock.patch(target, **kwargs)
        p = m.start()
        self.addCleanup(m.stop)
        setattr(self, attr, p)

    # prefer python3 read_file over readfp but allow fallback
    def parse_and_read(self, contents):
        parser = ConfigParser()
        if hasattr(parser, 'read_file'):
            parser.read_file(contents)
        elif hasattr(parser, 'readfp'):
            # pylint: disable=W1505
            parser.readfp(contents)
        return parser


class CiTestCase(TestCase):
    """This is the preferred test case base class unless user
       needs other test case classes below."""

    # Subclass overrides for specific test behavior
    # Whether or not a unit test needs logfile setup
    with_logs = False

    def setUp(self):
        super(CiTestCase, self).setUp()
        if self.with_logs:
            # Create a log handler so unit tests can search expected logs.
            self.logger = logging.getLogger()
            self.logs = six.StringIO()
            formatter = logging.Formatter('%(levelname)s: %(message)s')
            handler = logging.StreamHandler(self.logs)
            handler.setFormatter(formatter)
            self.old_handlers = self.logger.handlers
            self.logger.handlers = [handler]

    def tearDown(self):
        if self.with_logs:
            # Remove the handler we setup
            logging.getLogger().handlers = self.old_handlers
        super(CiTestCase, self).tearDown()

    def tmp_dir(self, dir=None, cleanup=True):
        # return a full path to a temporary directory that will be cleaned up.
        if dir is None:
            tmpd = tempfile.mkdtemp(
                prefix="ci-%s." % self.__class__.__name__)
        else:
            tmpd = tempfile.mkdtemp(dir=dir)
        self.addCleanup(functools.partial(shutil.rmtree, tmpd))
        return tmpd

    def tmp_path(self, path, dir=None):
        # return an absolute path to 'path' under dir.
        # if dir is None, one will be created with tmp_dir()
        # the file is not created or modified.
        if dir is None:
            dir = self.tmp_dir()
        return os.path.normpath(os.path.abspath(os.path.join(dir, path)))

    def sys_exit(self, code):
        """Provide a wrapper around sys.exit for python 2.6

        In 2.6, this code would produce 'cm.exception' with value int(2)
        rather than the SystemExit that was raised by sys.exit(2).
            with assertRaises(SystemExit) as cm:
                sys.exit(2)
        """
        raise SystemExit(code)


class ResourceUsingTestCase(CiTestCase):

    def setUp(self):
        super(ResourceUsingTestCase, self).setUp()
        self.resource_path = None

    def resourceLocation(self, subname=None):
        if self.resource_path is None:
            paths = [
                os.path.join('tests', 'data'),
                os.path.join('data'),
                os.path.join(os.pardir, 'tests', 'data'),
                os.path.join(os.pardir, 'data'),
            ]
            for p in paths:
                if os.path.isdir(p):
                    self.resource_path = p
                    break
        self.assertTrue((self.resource_path and
                         os.path.isdir(self.resource_path)),
                        msg="Unable to locate test resource data path!")
        if not subname:
            return self.resource_path
        return os.path.join(self.resource_path, subname)

    def readResource(self, name):
        where = self.resourceLocation(name)
        with open(where, 'r') as fh:
            return fh.read()

    def getCloudPaths(self, ds=None):
        tmpdir = tempfile.mkdtemp()
        self.addCleanup(shutil.rmtree, tmpdir)
        cp = ch.Paths({'cloud_dir': tmpdir,
                       'templates_dir': self.resourceLocation()},
                      ds=ds)
        return cp


class FilesystemMockingTestCase(ResourceUsingTestCase):

    def setUp(self):
        super(FilesystemMockingTestCase, self).setUp()
        self.patched_funcs = ExitStack()

    def tearDown(self):
        self.patched_funcs.close()
        ResourceUsingTestCase.tearDown(self)

    def replicateTestRoot(self, example_root, target_root):
        real_root = self.resourceLocation()
        real_root = os.path.join(real_root, 'roots', example_root)
        for (dir_path, _dirnames, filenames) in os.walk(real_root):
            real_path = dir_path
            make_path = rebase_path(real_path[len(real_root):], target_root)
            util.ensure_dir(make_path)
            for f in filenames:
                real_path = util.abs_join(real_path, f)
                make_path = util.abs_join(make_path, f)
                shutil.copy(real_path, make_path)

    def patchUtils(self, new_root):
        patch_funcs = {
            util: [('write_file', 1),
                   ('append_file', 1),
                   ('load_file', 1),
                   ('ensure_dir', 1),
                   ('chmod', 1),
                   ('delete_dir_contents', 1),
                   ('del_file', 1),
                   ('sym_link', -1),
                   ('copy', -1)],
        }
        for (mod, funcs) in patch_funcs.items():
            for (f, am) in funcs:
                func = getattr(mod, f)
                trap_func = retarget_many_wrapper(new_root, am, func)
                self.patched_funcs.enter_context(
                    mock.patch.object(mod, f, trap_func))

        # Handle subprocess calls
        func = getattr(util, 'subp')

        def nsubp(*_args, **_kwargs):
            return ('', '')

        self.patched_funcs.enter_context(
            mock.patch.object(util, 'subp', nsubp))

        def null_func(*_args, **_kwargs):
            return None

        for f in ['chownbyid', 'chownbyname']:
            self.patched_funcs.enter_context(
                mock.patch.object(util, f, null_func))

    def patchOS(self, new_root):
        patch_funcs = {
            os.path: [('isfile', 1), ('exists', 1),
                      ('islink', 1), ('isdir', 1)],
            os: [('listdir', 1), ('mkdir', 1),
                 ('lstat', 1), ('symlink', 2)],
        }
        for (mod, funcs) in patch_funcs.items():
            for f, nargs in funcs:
                func = getattr(mod, f)
                trap_func = retarget_many_wrapper(new_root, nargs, func)
                self.patched_funcs.enter_context(
                    mock.patch.object(mod, f, trap_func))

    def patchOpen(self, new_root):
        trap_func = retarget_many_wrapper(new_root, 1, open)
        name = 'builtins.open' if PY3 else '__builtin__.open'
        self.patched_funcs.enter_context(mock.patch(name, trap_func))

    def patchStdoutAndStderr(self, stdout=None, stderr=None):
        if stdout is not None:
            self.patched_funcs.enter_context(
                mock.patch.object(sys, 'stdout', stdout))
        if stderr is not None:
            self.patched_funcs.enter_context(
                mock.patch.object(sys, 'stderr', stderr))

    def reRoot(self, root=None):
        if root is None:
            root = self.tmp_dir()
        self.patchUtils(root)
        self.patchOS(root)
        return root


class HttprettyTestCase(CiTestCase):
    # necessary as http_proxy gets in the way of httpretty
    # https://github.com/gabrielfalcao/HTTPretty/issues/122

    def setUp(self):
        self.restore_proxy = os.environ.get('http_proxy')
        if self.restore_proxy is not None:
            del os.environ['http_proxy']
        super(HttprettyTestCase, self).setUp()

    def tearDown(self):
        if self.restore_proxy:
            os.environ['http_proxy'] = self.restore_proxy
        super(HttprettyTestCase, self).tearDown()


def populate_dir(path, files):
    if not os.path.exists(path):
        os.makedirs(path)
    ret = []
    for (name, content) in files.items():
        p = os.path.sep.join([path, name])
        util.ensure_dir(os.path.dirname(p))
        with open(p, "wb") as fp:
            if isinstance(content, six.binary_type):
                fp.write(content)
            else:
                fp.write(content.encode('utf-8'))
            fp.close()
        ret.append(p)

    return ret


def dir2dict(startdir, prefix=None):
    flist = {}
    if prefix is None:
        prefix = startdir
    for root, dirs, files in os.walk(startdir):
        for fname in files:
            fpath = os.path.join(root, fname)
            key = fpath[len(prefix):]
            flist[key] = util.load_file(fpath)
    return flist


def wrap_and_call(prefix, mocks, func, *args, **kwargs):
    """
    call func(args, **kwargs) with mocks applied, then unapplies mocks
    nicer to read than repeating dectorators on each function

    prefix: prefix for mock names (e.g. 'cloudinit.stages.util') or None
    mocks: dictionary of names (under 'prefix') to mock and either
        a return value or a dictionary to pass to the mock.patch call
    func: function to call with mocks applied
    *args,**kwargs: arguments for 'func'

    return_value: return from 'func'
    """
    delim = '.'
    if prefix is None:
        prefix = ''
    prefix = prefix.rstrip(delim)
    unwraps = []
    for fname, kw in mocks.items():
        if prefix:
            fname = delim.join((prefix, fname))
        if not isinstance(kw, dict):
            kw = {'return_value': kw}
        p = mock.patch(fname, **kw)
        p.start()
        unwraps.append(p)
    try:
        return func(*args, **kwargs)
    finally:
        for p in unwraps:
            p.stop()


try:
    skipIf = unittest.skipIf
except AttributeError:
    # Python 2.6.  Doesn't have to be high fidelity.
    def skipIf(condition, reason):
        def decorator(func):
            def wrapper(*args, **kws):
                if condition:
                    return func(*args, **kws)
                else:
                    print(reason, file=sys.stderr)
            return wrapper
        return decorator


# older versions of mock do not have the useful 'assert_not_called'
if not hasattr(mock.Mock, 'assert_not_called'):
    def __mock_assert_not_called(mmock):
        if mmock.call_count != 0:
            msg = ("[citest] Expected '%s' to not have been called. "
                   "Called %s times." %
                   (mmock._mock_name or 'mock', mmock.call_count))
            raise AssertionError(msg)
    mock.Mock.assert_not_called = __mock_assert_not_called


# older unittest2.TestCase (centos6) do not have assertRaisesRegex
# And setting assertRaisesRegex to assertRaisesRegexp causes
# https://github.com/PyCQA/pylint/issues/1653 . So the workaround.
if not hasattr(unittest2.TestCase, 'assertRaisesRegex'):
    def _tricky(*args, **kwargs):
        return unittest2.TestCase.assertRaisesRegexp
    unittest2.TestCase.assertRaisesRegex = _tricky

# vi: ts=4 expandtab