path: root/passlib/tests/utils.py

"""helpers for passlib unittests"""
#=========================================================
#imports
#=========================================================
from __future__ import with_statement
#core
import atexit
import logging; log = logging.getLogger(__name__)
import re
import os
import sys
import tempfile
from passlib.exc import PasslibHashWarning
from passlib.utils.compat import PY27, PY_MIN_32, PY3
from warnings import warn

try:
    import unittest2 as unittest
    ut_version = 2
except ImportError:
    import unittest
    if PY27 or PY_MIN_32:
        ut_version = 2
    else:
        # XXX: issue warning and deprecate support sometime?
        ut_version = 1

import warnings
from warnings import warn

#site
if ut_version < 2:
    #used to provide replacement skipTest() method
    from nose.plugins.skip import SkipTest
#pkg
from passlib.exc import MissingBackendError
import passlib.registry as registry
from passlib.utils import has_rounds_info, has_salt_info, rounds_cost_values, \
                          classproperty, rng, getrandstr, is_ascii_safe, to_native_str
from passlib.utils.compat import b, bytes, iteritems, irange, callable, \
                                 sb_types, exc_err, u, unicode
import passlib.utils.handlers as uh
#local
__all__ = [
    #util funcs
    'enable_option',
    'Params',
    'set_file', 'get_file',

    #unit testing
    'TestCase',
    'HandlerCase',
    'enable_backend_case',
    'create_backend_case',

    #flags
    'gae_env',
]

#figure out if we're running under GAE...
#some tests (eg FS related) should be skipped.
    #XXX: is there better way to do this?
try:
    import google.appengine
except ImportError:
    gae_env = False
else:
    gae_env = True

#=========================================================
#option flags
#=========================================================
DEFAULT_TESTS = ""

tests = set(
    v.strip()
    for v
    in os.environ.get("PASSLIB_TESTS", DEFAULT_TESTS).lower().split(",")
    )

def enable_option(*names):
    """check if a given test should be included based on the env var.

    test flags:
        all-backends    test all backends, even the inactive ones
        cover           enable minor tweaks to maximize coverage testing
        all             run all tests
    """
    return 'all' in tests or any(name in tests for name in names)

#=========================================================
#misc utility funcs
#=========================================================
class Params(object):
    "helper to represent params for function call"

    @classmethod
    def norm(cls, value):
        if isinstance(value, cls):
            return value
        if isinstance(value, (list,tuple)):
            return cls(*value)
        return cls(**value)

    def __init__(self, *args, **kwds):
        self.args = args
        self.kwds = kwds

    def render(self, offset=0):
        """render parenthesized parameters"""
        txt = ''
        for a in self.args[offset:]:
            txt += "%r, " % (a,)
        kwds = self.kwds
        for k in sorted(kwds):
            txt += "%s=%r, " % (k, kwds[k])
        if txt.endswith(", "):
            txt = txt[:-2]
        return txt

def set_file(path, content):
    "set file to specified bytes"
    if isinstance(content, unicode):
        content = content.encode("utf-8")
    with open(path, "wb") as fh:
        fh.write(content)

def get_file(path):
    "read file as bytes"
    with open(path, "rb") as fh:
        return fh.read()

#=========================================================
#custom test base
#=========================================================
class TestCase(unittest.TestCase):
    """passlib-specific test case class

    this class mainly overriddes many of the common assert methods
    so to give a default message which includes the values
    as well as the class-specific case_prefix string.
    this latter bit makes the output of various test cases
    easier to distinguish from eachother.
    """

    #=============================================================
    #make it ease for test cases to add common prefix to all descs
    #=============================================================
    #: string or method returning string - prepended to all tests in TestCase
    case_prefix = None

    #: flag to disable feature
    longDescription = True

    def shortDescription(self):
        "wrap shortDescription() method to prepend case_prefix"
        desc = super(TestCase, self).shortDescription()
        if desc is None:
            #would still like to add prefix, but munges things up.
            return None
        prefix = self.case_prefix
        if prefix and self.longDescription:
            if callable(prefix):
                prefix = prefix()
            desc = "%s: %s" % (prefix, desc)
        return desc

    #============================================================
    #hack to set UT2 private skip attrs to mirror nose's __test__ attr
    #============================================================
    if ut_version >= 2:

        @classproperty
        def __unittest_skip__(cls):
            # make this mirror nose's '__test__' attr
            return not getattr(cls, "__test__", True)

    @classproperty
    def __test__(cls):
        # nose uses to this to skip tests. overridding this to
        # skip classes with '__<cls>_unittest_skip' set - that way
        # we can omit specific classes without affecting subclasses.
        name = cls.__name__
        if name.startswith("_"):
            return False
        if getattr(cls, "_%s__unittest_skip" % name, False):
            return False
        return True

    __unittest_skip = True

    #============================================================
    # tweak msg formatting for some assert methods
    #============================================================
    longMessage = True #override python default (False)

    def _formatMessage(self, msg, std):
        "override UT2's _formatMessage - only use longMessage if msg ends with ':'"
        if not msg:
            return std
        if not self.longMessage or not msg.endswith(":"):
            return msg.rstrip(":")
        return '%s %s' % (msg, std)

    #============================================================
    #override some unittest1 methods to support _formatMessage
    #============================================================
    if ut_version < 2:

        def assertEqual(self, real, correct, msg=None):
            if real != correct:
                std = "got %r, expected would equal %r" % (real, correct)
                msg = self._formatMessage(msg, std)
                raise self.failureException(msg)

        def assertNotEqual(self, real, correct, msg=None):
            if real == correct:
                std = "got %r, expected would not equal %r" % (real, correct)
                msg = self._formatMessage(msg, std)
                raise self.failureException(msg)

        assertEquals = assertEqual
        assertNotEquals = assertNotEqual

    #NOTE: overriding this even under UT2.
    #FIXME: this doesn't support the fancy context manager UT2 provides.
    def assertRaises(self, _exc_type, _callable, *args, **kwds):
        #NOTE: overriding this for format ability,
        #      but ALSO adding "__msg__" kwd so we can set custom msg
        msg = kwds.pop("__msg__", None)
        if _callable is None:
            return super(TestCase, self).assertRaises(_exc_type, None,
                                                      *args, **kwds)
        try:
            result = _callable(*args, **kwds)
        except _exc_type:
            return
        std = "function returned %r, expected it to raise %r" % (result,
                                                                 _exc_type)
        raise self.failureException(self._formatMessage(msg, std))

    #===============================================================
    #backport some methods from unittest2
    #===============================================================
    if ut_version < 2:

        def assertIs(self, real, correct, msg=None):
            if real is not correct:
                std = "got %r, expected would be %r" % (real, correct)
                msg = self._formatMessage(msg, std)
                raise self.failureException(msg)

        def assertIsNot(self, real, correct, msg=None):
            if real is correct:
                std = "got %r, expected would not be %r" % (real, correct)
                msg = self._formatMessage(msg, std)
                raise self.failureException(msg)

        def assertIsInstance(self, obj, klass, msg=None):
            if not isinstance(obj, klass):
                std = "got %r, expected instance of %r" % (obj, klass)
                msg = self._formatMessage(msg, std)
                raise self.failureException(msg)

        def skipTest(self, reason):
            raise SkipTest(reason)

        def assertAlmostEqual(self, first, second, places=None, msg=None, delta=None):
            """Fail if the two objects are unequal as determined by their
               difference rounded to the given number of decimal places
               (default 7) and comparing to zero, or by comparing that the
               between the two objects is more than the given delta.

               Note that decimal places (from zero) are usually not the same
               as significant digits (measured from the most signficant digit).

               If the two objects compare equal then they will automatically
               compare almost equal.
            """
            if first == second:
                # shortcut
                return
            if delta is not None and places is not None:
                raise TypeError("specify delta or places not both")

            if delta is not None:
                if abs(first - second) <= delta:
                    return

                standardMsg = '%s != %s within %s delta' % (repr(first),
                                                            repr(second),
                                                            repr(delta))
            else:
                if places is None:
                    places = 7

                if round(abs(second-first), places) == 0:
                    return

                standardMsg = '%s != %s within %r places' % (repr(first),
                                                              repr(second),
                                                              places)
            msg = self._formatMessage(msg, standardMsg)
            raise self.failureException(msg)

    if not hasattr(unittest.TestCase, "assertRegex"):
        # assertRegexpMatches() added in 2.7/UT2 and 3.1, renamed to
        # assertRegex() in 3.2; this code ensures assertRegex() is defined.
        if hasattr(unittest.TestCase, "assertRegexpMatches"):
            assertRegex = unittest.TestCase.assertRegexpMatches
        else:
            def assertRegex(self, text, expected_regex, msg=None):
                """Fail the test unless the text matches the regular expression."""
                if isinstance(expected_regex, sb_types):
                    assert expected_regex, "expected_regex must not be empty."
                    expected_regex = re.compile(expected_regex)
                if not expected_regex.search(text):
                    msg = msg or "Regex didn't match"
                    msg = '%s: %r not found in %r' % (msg, expected_regex.pattern, text)
                    raise self.failureException(msg)

    #============================================================
    #add some custom methods
    #============================================================
    def assertFunctionResults(self, func, cases):
        """helper for running through function calls.

        func should be the function to call.
        cases should be list of Param instances,
        where first position argument is expected return value,
        and remaining args and kwds are passed to function.
        """
        for elem in cases:
            elem = Params.norm(elem)
            correct = elem.args[0]
            result = func(*elem.args[1:], **elem.kwds)
            msg = "error for case %r:" % (elem.render(1),)
            self.assertEqual(result, correct, msg)

    def assertWarning(self, warning,
                             message_re=None, message=None,
                             category=None,
                             ##filename=None, filename_re=None,
                             ##lineno=None,
                             msg=None,
                             ):
        "check if WarningMessage instance (as returned by catch_warnings) matches parameters"

        # check input type
        if hasattr(warning, "category"):
            # resolve WarningMessage -> Warning, but preserve original
            wmsg = warning
            warning = warning.message
        else:
            # no original WarningMessage, passed raw Warning
            wmsg = None

        #tests that can use a warning instance or WarningMessage object
        if message:
            self.assertEqual(str(warning), message, msg)
        if message_re:
            self.assertRegex(str(warning), message_re, msg)
        if category:
            self.assertIsInstance(warning, category, msg)

        #commented out until needed...
        ###tests that require a WarningMessage object
        ##if filename or filename_re:
        ##    if not wmsg:
        ##        raise TypeError("can't read filename from warning object")
        ##    real = wmsg.filename
        ##    if real.endswith(".pyc") or real.endswith(".pyo"):
        ##        #FIXME: should use a stdlib call to resolve this back
        ##        #       to original module's path
        ##        real = real[:-1]
        ##    if filename:
        ##        self.assertEqual(real, filename, msg)
        ##    if filename_re:
        ##        self.assertRegex(real, filename_re, msg)
        ##if lineno:
        ##    if not wmsg:
        ##        raise TypeError("can't read lineno from warning object")
        ##    self.assertEqual(wmsg.lineno, lineno, msg)

    def assertWarningList(self, wlist, desc=None, msg=None):
        """check that warning list (e.g. from catch_warnings) matches pattern"""
        # TODO: make this display better diff of *which* warnings did not match,
        # and make use of _formatWarning below.
        if not isinstance(desc, (list,tuple)):
            desc = [] if desc is None else [desc]
        for idx, entry in enumerate(desc):
            if isinstance(entry, str):
                entry = dict(message_re=entry)
            elif isinstance(entry, type) and issubclass(entry, Warning):
                entry = dict(category=entry)
            elif not isinstance(entry, dict):
                raise TypeError("entry must be str, warning, or dict")
            try:
                data = wlist[idx]
            except IndexError:
                break
            self.assertWarning(data, msg=msg, **entry)
        else:
            if len(wlist) == len(desc):
                return
        std = "expected %d warnings, found %d: wlist=%s desc=%r" % \
                (len(desc), len(wlist), self._formatWarningList(wlist), desc)
        raise self.failureException(self._formatMessage(msg, std))

    def _formatWarning(self, entry):
        tail = ""
        if hasattr(entry, "message"):
            # WarningMessage instance.
            tail = " filename=%r lineno=%r" % (entry.filename, entry.lineno)
            if entry.line:
                tail += " line=%r" % (entry.line,)
            entry = entry.message
        cls = type(entry)
        return "<%s.%s message=%r%s>" % (cls.__module__, cls.__name__,
                                           str(entry), tail)

    def _formatWarningList(self, wlist):
        return "[%s]" % ", ".join(self._formatWarning(entry) for entry in wlist)

    def consumeWarningList(self, wlist, *args, **kwds):
        """assertWarningList() variant that clears list afterwards"""
        self.assertWarningList(wlist, *args, **kwds)
        del wlist[:]

    #============================================================
    #eoc
    #============================================================

#=========================================================
#other unittest helpers
#=========================================================
RESERVED_BACKEND_NAMES = ["any", "default"]

class HandlerCase(TestCase):
    """base class for testing password hash handlers (esp passlib.utils.handlers subclasses)

    In order to use this to test a handler,
    create a subclass will all the appropriate attributes
    filled as listed in the example below,
    and run the subclass via unittest.

    .. todo::

        Document all of the options HandlerCase offers.

    .. note::

        This is subclass of :class:`unittest.TestCase`
        (or :class:`unittest2.TestCase` if available).
    """
    #=========================================================
    # attrs to be filled in by subclass for testing specific handler
    #=========================================================

    #--------------------------------------------------
    # handler setup
    #--------------------------------------------------

    # specify handler object here (required)
    handler = None

    # run tests against specific backend (optional, when applicable)
    backend = None

    #--------------------------------------------------
    # test vectors
    #--------------------------------------------------

    # list of (secret, hash) tuples which are known to be correct
    known_correct_hashes = []

    # list of (config, secret, hash) tuples are known to be correct
    known_correct_configs = []

    # list of (alt_hash, secret, hash) tuples, where alt_hash is a hash
    # using an alternate representation that should be recognized and verify
    # correctly, but should be corrected to match hash when passed through
    # genhash()
    known_alternate_hashes = []

    # hashes so malformed they aren't even identified properly
    known_unidentified_hashes = []

    # hashes which are identifiabled but malformed - they should identify()
    # as True, but cause an error when passed to genhash/verify.
    known_malformed_hashes = []

    # list of (handler name, hash) pairs for other algorithm's hashes that
    # handler shouldn't identify as belonging to it this list should generally
    # be sufficient (if handler name in list, that entry will be skipped)
    known_other_hashes = [
        ('des_crypt', '6f8c114b58f2c'),
        ('md5_crypt', '$1$dOHYPKoP$tnxS1T8Q6VVn3kpV8cN6o.'),
        ('sha512_crypt', "$6$rounds=123456$asaltof16chars..$BtCwjqMJGx5hrJhZywW"
         "vt0RLE8uZ4oPwcelCjmw2kSYu.Ec6ycULevoBK25fs2xXgMNrCzIMVcgEJAstJeonj1"),
    ]

    # passwords used to test basic encrypt behavior - generally
    # don't need to be overidden.
    stock_passwords = [
        u("test"),
        u("\u20AC\u00A5$"),
        b('\xe2\x82\xac\xc2\xa5$')
    ]

    #--------------------------------------------------
    # option flags
    #--------------------------------------------------

    # maximum number of chars which hash will include in digest.
    # ``None`` (the default) indicates the hash uses ALL of the password.
    secret_size = None

    # whether hash is case insensitive
    secret_case_insensitive = False

    # flag if scheme accepts ALL hash strings (e.g. plaintext)
    accepts_all_hashes = False

    # flag indicating "disabled account" handler (e.g. unix_disabled)
    is_disabled_handler = False

    # flag/hack to filter PasslibHashWarning issued by test_72_configs()
    filter_config_warnings = False

    #=========================================================
    # alg interface helpers - allows subclass to overide how
    # default tests invoke the handler (eg for context_kwds)
    #=========================================================

    def do_encrypt(self, secret, **kwds):
        "call handler's encrypt method with specified options"
        return self.handler.encrypt(secret, **kwds)

    def do_verify(self, secret, hash, **kwds):
        "call handler's verify method"
        return self.handler.verify(secret, hash, **kwds)

    def do_identify(self, hash):
        "call handler's identify method"
        return self.handler.identify(hash)

    def do_genconfig(self, **kwds):
        "call handler's genconfig method with specified options"
        return self.handler.genconfig(**kwds)

    def do_genhash(self, secret, config, **kwds):
        "call handler's genhash method with specified options"
        return self.handler.genhash(secret, config, **kwds)

    #=========================================================
    # support
    #=========================================================
    @property
    def supports_config_string(self):
        return self.do_genconfig() is not None

    def iter_known_hashes(self):
        "iterate through known (secret, hash) pairs"
        for secret, hash in self.known_correct_hashes:
            yield secret, hash
        for config, secret, hash in self.known_correct_configs:
            yield secret, hash
        for alt, secret, hash in self.known_alternate_hashes:
            yield secret, hash

    def get_sample_hash(self):
        "test random sample secret/hash pair"
        known = list(self.iter_known_hashes())
        return rng.choice(known)

    def check_verify(self, secret, hash, msg=None, negate=False):
        "helper to check verify() outcome, honoring is_disabled_handler"
        result = self.do_verify(secret, hash)
        self.assertTrue(result is True or result is False,
                        "verify() returned non-boolean value: %r" % (result,))
        if self.is_disabled_handler or negate:
            if not result:
                return
            if not msg:
                msg = ("verify incorrectly returned True: secret=%r, hash=%r" %
                       (secret, hash))
            raise self.failureException(msg)
        else:
            if result:
                return
            if not msg:
                msg = "verify failed: secret=%r, hash=%r" % (secret, hash)
            raise self.failureException(msg)

    #=========================================================
    # internal class attrs
    #=========================================================
    __unittest_skip = True

    #optional prefix to prepend to name of test method as it's called,
    #useful when multiple handler test classes being run.
    #default behavior should be sufficient
    def case_prefix(self):
        handler = self.handler
        name = handler.name
        if hasattr(handler, "get_backend"):
            name += " (%s backend)" % (handler.get_backend(),)
        return name

    #=========================================================
    # internal instance attrs
    #=========================================================
    # indicates safe_crypt() has been patched to use another backend of handler.
    using_patched_crypt = False

    # backup of original utils.os_crypt before it was patched.
    _orig_crypt = None

    # backup of original backend before test started
    _orig_backend = None

    #=========================================================
    # setup / cleanup
    #=========================================================
    def setUp(self):
        # backup warning filter state; set to display all warnings during tests;
        # and restore filter state after test.
        ctx = catch_warnings()
        ctx.__enter__()
        self._restore_warnings = ctx.__exit__
        warnings.resetwarnings()
        warnings.simplefilter("always")

        # if needed, select specific backend for duration of test
        handler = self.handler
        backend = self.backend
        if backend:
            if not hasattr(handler, "set_backend"):
                raise RuntimeError("handler doesn't support multiple backends")
            if backend == "os_crypt" and not handler.has_backend("os_crypt"):
                self._patch_safe_crypt()
            self._orig_backend = handler.get_backend()
            handler.set_backend(backend)

    def _patch_safe_crypt(self):
        """if crypt() doesn't support current hash alg, this patches
        safe_crypt() so that it transparently uses another one of the handler's
        backends, so that we can go ahead and test as much of code path
        as possible.
        """
        handler = self.handler
        alt_backend = _has_other_backends(handler, "os_crypt")
        if not alt_backend:
            raise AssertionError("handler has no available backends!")
        import passlib.utils as mod
        def crypt_stub(secret, hash):
            with temporary_backend(handler, alt_backend):
                hash = handler.genhash(secret, hash)
            assert isinstance(hash, str)
            return hash
        self._orig_crypt = mod._crypt
        mod._crypt = crypt_stub
        self.using_patched_crypt = True

    def tearDown(self):
        # unpatch safe_crypt()
        if self._orig_crypt:
            import passlib.utils as mod
            mod._crypt = self._orig_crypt

        # restore original backend
        if self._orig_backend:
            self.handler.set_backend(self._orig_backend)

        # restore warning filters
        self._restore_warnings()

    #=========================================================
    # basic tests
    #=========================================================
    def test_01_required_attributes(self):
        "validate required attributes"
        handler = self.handler
        def ga(name):
            return getattr(handler, name, None)

        name = ga("name")
        self.assertTrue(name, "name not defined:")
        self.assertIsInstance(name, str, "name must be native str")
        self.assertTrue(name.lower() == name, "name not lower-case:")
        self.assertTrue(re.match("^[a-z0-9_]+$", name),
                        "name must be alphanum + underscore: %r" % (name,))

        settings = ga("setting_kwds")
        self.assertTrue(settings is not None, "setting_kwds must be defined:")
        self.assertIsInstance(settings, tuple, "setting_kwds must be a tuple:")

        context = ga("context_kwds")
        self.assertTrue(context is not None, "context_kwds must be defined:")
        self.assertIsInstance(context, tuple, "context_kwds must be a tuple:")

    def test_02_genconfig(self):
        "test basic genconfig() behavior"
        # this also tests identify/verify/genhash have basic functionality.

        if self.supports_config_string:
            # try to generate a config string, make sure it's right type
            config = self.do_genconfig()
            self.assertIsInstance(config, str,
                "genconfig() failed to return native string: %r" % (config,))

            # config should be positively identified by handler
            self.assertTrue(self.do_identify(config),
                "identify() failed to identify genconfig() output: %r" %
                (config,))

            # verify() should throw error for config strings.
            self.assertRaises(ValueError, self.do_verify, 'stub', config,
                __msg__="verify() failed to reject genconfig() output: %r" %
                (config,))

            # genhash should accept genconfig output
            result = self.do_genhash('stub', config)
            self.assertIsInstance(result, str,
                "genhash() failed to return native string: %r" % (result,))

        else:
            self.assertIs(self.do_genconfig(), None)
            # identify/verify/genhash are tested against 'None'
            # in test_76_null()

    def test_03_encrypt(self):
        "test basic encrypt() behavior"
        # this also tests identify/verify/genhash have basic functionality.

        # test against stock passwords
        for secret in self.stock_passwords:

            # encrypt should generate hash...
            result = self.do_encrypt(secret)
            self.assertIsInstance(result, str,
                                  "encrypt must return native str:")

            # which should be positively identifiable...
            self.assertTrue(self.do_identify(result))

            # and should verify correctly...
            self.check_verify(secret, result)

            # and should NOT verify correctly
            assert secret != 'stub'
            self.check_verify('stub', result, negate=True)

            # and genhash should reproduce original
            other = self.do_genhash(secret, result)
            self.assertIsInstance(other, str,
                                  "genhash must return native str:")
            self.assertEqual(other, result, "genhash() failed to reproduce "
                             "hash: secret=%r hash=%r: result=%r" %
                             (secret, hash, result))

    def test_04_backends(self):
        "test multi-backend support"
        handler = self.handler
        if not hasattr(handler, "set_backend"):
            raise self.skipTest("handler only has one backend")
        with temporary_backend(handler):
            for backend in handler.backends:

                # validate backend name
                self.assertIsInstance(backend, str)
                self.assertNotIn(backend, RESERVED_BACKEND_NAMES,
                                 "invalid backend name: %r" % (backend,))

                # ensure has_backend() returns bool value
                ret = handler.has_backend(backend)
                if ret is True:
                    # verify backend can be loaded
                    handler.set_backend(backend)
                    self.assertEqual(handler.get_backend(), backend)

                elif ret is False:
                    # verify backend CAN'T be loaded
                    self.assertRaises(MissingBackendError, handler.set_backend,
                                      backend)

                else:
                    # didn't return boolean object. commonly fails due to
                    # use of 'classmethod' decorator instead of 'classproperty'
                    raise TypeError("has_backend(%r) returned invalid "
                                    "value: %r" % (backend, ret))

    #==============================================================
    # salts
    #==============================================================
    def require_salt(self):
        if 'salt' not in self.handler.setting_kwds:
            raise self.skipTest("handler doesn't have salt")

    def require_salt_info(self):
        self.require_salt()
        if not has_salt_info(self.handler):
            raise self.skipTest("handler doesn't provide salt info")

    def test_10_optional_salt_attributes(self):
        "validate optional salt attributes"
        self.require_salt_info()

        AssertionError = self.failureException
        cls = self.handler

        #check max_salt_size
        mx_set = (cls.max_salt_size is not None)
        if mx_set and cls.max_salt_size < 1:
            raise AssertionError("max_salt_chars must be >= 1")

        #check min_salt_size
        if cls.min_salt_size < 0:
            raise AssertionError("min_salt_chars must be >= 0")
        if mx_set and cls.min_salt_size > cls.max_salt_size:
            raise AssertionError("min_salt_chars must be <= max_salt_chars")

        #check default_salt_size
        if cls.default_salt_size < cls.min_salt_size:
            raise AssertionError("default_salt_size must be >= min_salt_size")
        if mx_set and cls.default_salt_size > cls.max_salt_size:
            raise AssertionError("default_salt_size must be <= max_salt_size")

        #check for 'salt_size' keyword
        if 'salt_size' not in cls.setting_kwds and \
                (not mx_set or cls.min_salt_size < cls.max_salt_size):
            # NOTE: only bothering to issue warning if default_salt_size
            # isn't maxed out
            if (not mx_set or cls.default_salt_size < cls.max_salt_size):
                warn("%s: hash handler supports range of salt sizes, "
                     "but doesn't offer 'salt_size' setting" % (cls.name,))

        #check salt_chars & default_salt_chars
        if cls.salt_chars:
            if not cls.default_salt_chars:
                raise AssertionError("default_salt_chars must not be empty")
            if any(c not in cls.salt_chars for c in cls.default_salt_chars):
                raise AssertionError("default_salt_chars must be subset of salt_chars: %r not in salt_chars" % (c,))
        else:
            if not cls.default_salt_chars:
                raise AssertionError("default_salt_chars MUST be specified if salt_chars is empty")

    def test_11_unique_salt(self):
        "test encrypt() / genconfig() creates new salt each time"
        self.require_salt()
        c1 = self.do_genconfig()
        c2 = self.do_genconfig()
        self.assertIsInstance(c1, str, "genconfig() must return native str:")
        self.assertIsInstance(c2, str, "genconfig() must return native str:")
        self.assertNotEqual(c1,c2)

    def test_12_min_salt_size(self):
        "test encrypt() / genconfig() honors min_salt_size"
        self.require_salt_info()

        handler = self.handler
        salt_char = handler.salt_chars[0:1]
        min_size = handler.min_salt_size

        #
        # check min is accepted
        #
        s1 = salt_char * min_size
        self.do_genconfig(salt=s1)

        self.do_encrypt('stub', salt_size=min_size)

        #
        # check min-1 is rejected
        #
        if min_size > 0:
            self.assertRaises(ValueError, self.do_genconfig,
                              salt=s1[:-1])

        self.assertRaises(ValueError, self.do_encrypt, 'stub',
                          salt_size=min_size-1)

    def test_13_max_salt_size(self):
        "test encrypt() / genconfig() honors max_salt_size"
        self.require_salt_info()

        handler = self.handler
        max_size = handler.max_salt_size
        salt_char = handler.salt_chars[0:1]

        if max_size is None:
            #
            # if it's not set, salt should never be truncated; so test it
            # with an unreasonably large salt.
            #
            s1 = salt_char * 1024
            c1 = self.do_genconfig(salt=s1)
            c2 = self.do_genconfig(salt=s1 + salt_char)
            self.assertNotEqual(c1, c2)

            self.do_encrypt('stub', salt_size=1024)

        else:
            #
            # check max size is accepted
            #
            s1 = salt_char * max_size
            c1 = self.do_genconfig(salt=s1)

            self.do_encrypt('stub', salt_size=max_size)

            #
            # check max size + 1 is rejected
            #
            s2 = s1 + salt_char
            self.assertRaises(ValueError, self.do_genconfig, salt=s2)

            self.assertRaises(ValueError, self.do_encrypt, 'stub',
                              salt_size=max_size+1)

            #
            # should accept too-large salt in relaxed mode
            #
            if _has_relaxed_setting(handler):
                with catch_warnings(record=True): # issues passlibhandlerwarning
                    c2 = self.do_genconfig(salt=s2, relaxed=True)
                self.assertEqual(c2, c1)

            #
            # if min_salt supports it, check smaller than mx is NOT truncated
            #
            if handler.min_salt_size < max_size:
                c3 = self.do_genconfig(salt=s1[:-1])
                self.assertNotEqual(c3, c1)

    def test_14_salt_chars(self):
        "test genconfig() honors salt_chars"
        self.require_salt_info()

        handler = self.handler
        mx = handler.max_salt_size
        mn = handler.min_salt_size
        cs = handler.salt_chars
        raw = isinstance(cs, bytes)

        # make sure all listed chars are accepted
        chunk = mx or 32
        for i in irange(0,len(cs),chunk):
            salt = cs[i:i+chunk]
            if len(salt) < mn:
                salt = (salt*(mn//len(salt)+1))[:chunk]
            self.do_genconfig(salt=salt)

        # check some invalid salt chars, make sure they're rejected
        source = u('\x00\xff')
        if raw:
            source = source.encode("latin-1")
        chunk = max(mn, 1)
        for c in source:
            if c not in cs:
                self.assertRaises(ValueError, self.do_genconfig, salt=c*chunk,
                                  __msg__="invalid salt char %r:" % (c,))

    #==============================================================
    # rounds
    #==============================================================
    def require_rounds_info(self):
        if not has_rounds_info(self.handler):
            raise self.skipTest("handler lacks rounds attributes")

    def test_20_optional_rounds_attributes(self):
        "validate optional rounds attributes"
        self.require_rounds_info()

        cls = self.handler
        AssertionError = self.failureException

        #check max_rounds
        if cls.max_rounds is None:
            raise AssertionError("max_rounds not specified")
        if cls.max_rounds < 1:
            raise AssertionError("max_rounds must be >= 1")

        #check min_rounds
        if cls.min_rounds < 0:
            raise AssertionError("min_rounds must be >= 0")
        if cls.min_rounds > cls.max_rounds:
            raise AssertionError("min_rounds must be <= max_rounds")

        #check default_rounds
        if cls.default_rounds is not None:
            if cls.default_rounds < cls.min_rounds:
                raise AssertionError("default_rounds must be >= min_rounds")
            if cls.default_rounds > cls.max_rounds:
                raise AssertionError("default_rounds must be <= max_rounds")

        #check rounds_cost
        if cls.rounds_cost not in rounds_cost_values:
            raise AssertionError("unknown rounds cost constant: %r" % (cls.rounds_cost,))

    def test_21_rounds_limits(self):
        "test encrypt() / genconfig() honors rounds limits"
        self.require_rounds_info()
        handler = self.handler
        min_rounds = handler.min_rounds

        # check min is accepted
        self.do_genconfig(rounds=min_rounds)
        self.do_encrypt('stub', rounds=min_rounds)

        # check min-1 is rejected
        self.assertRaises(ValueError, self.do_genconfig, rounds=min_rounds-1)
        self.assertRaises(ValueError, self.do_encrypt, 'stub',
                          rounds=min_rounds-1)

        # TODO: check relaxed mode clips min-1

        # handle max rounds
        max_rounds = handler.max_rounds
        if max_rounds is None:
            # check large value is accepted
            self.do_genconfig(rounds=(1<<31)-1)
        else:
            # check max is accepted
            self.do_genconfig(rounds=max_rounds)

            # check max+1 is rejected
            self.assertRaises(ValueError, self.do_genconfig,
                              rounds=max_rounds+1)
            self.assertRaises(ValueError, self.do_encrypt, 'stub',
                              rounds=max_rounds+1)

            # TODO: check relaxed mode clips max+1

    #==============================================================
    # idents
    #==============================================================
    def test_30_HasManyIdents(self):
        "validate HasManyIdents configuration"
        cls = self.handler
        if not isinstance(cls, type) or not issubclass(cls, uh.HasManyIdents):
            raise self.skipTest("handler doesn't derive from HasManyIdents")

        # check settings
        self.assertTrue('ident' in cls.setting_kwds)

        # check ident_values list
        for value in cls.ident_values:
            self.assertIsInstance(value, unicode,
                                  "cls.ident_values must be unicode:")
        self.assertTrue(len(cls.ident_values)>1,
                        "cls.ident_values must have 2+ elements:")

        # check default_ident value
        self.assertIsInstance(cls.default_ident, unicode,
                              "cls.default_ident must be unicode:")
        self.assertTrue(cls.default_ident in cls.ident_values,
                        "cls.default_ident must specify member of cls.ident_values")

        # check optional aliases list
        if cls.ident_aliases:
            for alias, ident in iteritems(cls.ident_aliases):
                self.assertIsInstance(alias, unicode,
                                      "cls.ident_aliases keys must be unicode:") #XXX: allow ints?
                self.assertIsInstance(ident, unicode,
                                      "cls.ident_aliases values must be unicode:")
                self.assertTrue(ident in cls.ident_values,
                                "cls.ident_aliases must map to cls.ident_values members: %r" % (ident,))

        # check constructor validates ident correctly.
        handler = cls
        hash = self.get_sample_hash()[1]
        kwds = _hobj_to_dict(handler.from_string(hash))
        del kwds['ident']

        # ... accepts good ident
        handler(ident=cls.default_ident, **kwds)

        # ... requires ident w/o defaults
        self.assertRaises(TypeError, handler, **kwds)

        # ... supplies default ident
        handler(use_defaults=True, **kwds)

        # ... rejects bad ident
        self.assertRaises(ValueError, handler, ident='xXx', **kwds)

    # TODO: check various supported idents

    #==============================================================
    # passwords
    #==============================================================
    def test_60_secret_size(self):
        "test password size limits"
        sc = self.secret_size
        base = "too many secrets" # 16 chars
        alt = 'x' # char that's not in base string
        if sc is not None:
            # hash only counts the first <sc> characters; eg: bcrypt, des-crypt

            # create & hash string that's exactly sc+1 chars
            secret = (base * (1+sc//16))[:sc+1]
            assert len(secret) == sc+1
            hash = self.do_encrypt(secret)

            # check sc value isn't too large by verifying that sc-1'th char
            # affects hash
            secret2 = secret[:-2] + alt + secret[-1]
            self.assertFalse(self.do_verify(secret2, hash),
                            "secret_size value is too large")

            # check sc value isn't too small by verifying adding sc'th char
            # *doesn't* affect hash
            secret3 = secret[:-1] + alt
            self.assertTrue(self.do_verify(secret3, hash),
                            "secret_size value is too small")

        else:
            # hash counts all characters; e.g. md5-crypt

            # NOTE: this doesn't do an exhaustive search to verify algorithm
            # doesn't have some cutoff point, it just tries
            # 1024-character string, and alters the last char.
            # as long as algorithm doesn't clip secret at point <1024,
            # the new secret shouldn't verify.
            secret = base * 64
            hash = self.do_encrypt(secret)
            secret2 = secret[:-1] + alt
            self.assertFalse(self.do_verify(secret2, hash),
                             "full password not used in digest")

    def test_61_case_sensitive(self):
        "test password case sensitivity"
        lower = 'test'
        upper = 'TEST'
        h1 = self.do_encrypt(lower)
        if self.secret_case_insensitive:
            self.assertTrue(self.do_verify(upper, h1),
                            "hash should not be case sensitive")
        else:
            self.assertFalse(self.do_verify(upper, h1),
                             "hash should be case sensitive")

    def test_62_null(self):
        "test password=None"
        _, hash = self.get_sample_hash()
        self.assertRaises(TypeError, self.do_encrypt, None)
        self.assertRaises(TypeError, self.do_genhash, None, hash)
        self.assertRaises(TypeError, self.do_verify, None, hash)

    #==============================================================
    # check identify(), verify(), genhash() against test vectors
    #==============================================================
    def is_secret_8bit(self, secret):
        return not is_ascii_safe(secret)

    def test_70_hashes(self):
        "test known hashes"
        # sanity check
        self.assertTrue(self.known_correct_hashes or self.known_correct_configs,
                        "test must set at least one of 'known_correct_hashes' "
                        "or 'known_correct_configs'")

        # run through known secret/hash pairs
        saw8bit = False
        for secret, hash in self.iter_known_hashes():
            if self.is_secret_8bit(secret):
                saw8bit = True

            # hash should be positively identified by handler
            self.assertTrue(self.do_identify(hash),
                "identify() failed to identify hash: %r" % (hash,))

            # secret should verify successfully against hash
            self.check_verify(secret, hash, "verify() of known hash failed: "
                              "secret=%r, hash=%r" % (secret, hash))

            # genhash() should reproduce same hash
            result = self.do_genhash(secret, hash)
            self.assertIsInstance(result, str,
                "genhash() failed to return native string: %r" % (result,))
            self.assertEqual(result, hash,  "genhash() failed to reproduce "
                "known hash: secret=%r, hash=%r: result=%r" %
                (secret, hash, result))

        # would really like all handlers to have at least one 8-bit test vector
        if not saw8bit:
            warn("%s: no 8-bit secrets tested" % self.__class__)

    def test_71_alternates(self):
        "test known alternate hashes"
        if not self.known_alternate_hashes:
            raise self.skipTest("no alternate hashes provided")

        for alt, secret, hash in self.known_alternate_hashes:

            # hash should be positively identified by handler
            self.assertTrue(self.do_identify(hash),
                "identify() failed to identify alternate hash: %r" %
                (hash,))

            # secret should verify successfully against hash
            self.check_verify(secret, alt, "verify() of known alternate hash "
                              "failed: secret=%r, hash=%r" % (secret, alt))

            # genhash() should reproduce canonical hash
            result = self.do_genhash(secret, alt)
            self.assertIsInstance(result, str,
                "genhash() failed to return native string: %r" % (result,))
            self.assertEqual(result, hash,  "genhash() failed to normalize "
                "known alternate hash: secret=%r, alt=%r, hash=%r: "
                "result=%r" % (secret, alt, hash, result))

    def test_72_configs(self):
        "test known config strings"
        # special-case handlers without settings
        if not self.handler.setting_kwds:
            self.assertFalse(self.known_correct_configs,
                            "handler should not have config strings")
            raise self.skipTest("hash has no settings")

        if not self.known_correct_configs:
            # XXX: make this a requirement?
            raise self.skipTest("no config strings provided")

        # make sure config strings work (hashes in list tested in test_70)
        if self.filter_config_warnings:
            warnings.filterwarnings("ignore", category=PasslibHashWarning)
        for config, secret, hash in self.known_correct_configs:

            # config should be positively identified by handler
            self.assertTrue(self.do_identify(config),
                "identify() failed to identify known config string: %r" %
                (config,))

            # verify() should throw error for config strings.
            self.assertRaises(ValueError, self.do_verify, secret, config,
                __msg__="verify() failed to reject config string: %r" %
                (config,))

            # genhash() should reproduce hash from config.
            result = self.do_genhash(secret, config)
            self.assertIsInstance(result, str,
                "genhash() failed to return native string: %r" % (result,))
            self.assertEqual(result, hash,  "genhash() failed to reproduce "
                "known hash from config: secret=%r, config=%r, hash=%r: "
                "result=%r" % (secret, config, hash, result))

    def test_73_unidentified(self):
        "test known unidentifiably-mangled strings"
        if not self.known_unidentified_hashes:
            raise self.skipTest("no unidentified hashes provided")
        for hash in self.known_unidentified_hashes:

            # identify() should reject these
            self.assertFalse(self.do_identify(hash),
                "identify() incorrectly identified known unidentifiable "
                "hash: %r" % (hash,))

            # verify() should throw error
            self.assertRaises(ValueError, self.do_verify, 'stub', hash,
                __msg__= "verify() failed to throw error for unidentifiable "
                "hash: %r" % (hash,))

            # genhash() should throw error
            self.assertRaises(ValueError, self.do_genhash, 'stub', hash,
                __msg__= "genhash() failed to throw error for unidentifiable "
                "hash: %r" % (hash,))

    def test_74_malformed(self):
        "test known identifiable-but-malformed strings"
        if not self.known_malformed_hashes:
            raise self.skipTest("no malformed hashes provided")
        for hash in self.known_malformed_hashes:

            # identify() should accept these
            self.assertTrue(self.do_identify(hash),
                "identify() failed to identify known malformed "
                "hash: %r" % (hash,))

            # verify() should throw error
            self.assertRaises(ValueError, self.do_verify, 'stub', hash,
                __msg__= "verify() failed to throw error for malformed "
                "hash: %r" % (hash,))

            # genhash() should throw error
            self.assertRaises(ValueError, self.do_genhash, 'stub', hash,
                __msg__= "genhash() failed to throw error for malformed "
                "hash: %r" % (hash,))

    def test_75_foreign(self):
        "test known foreign hashes"
        if self.accepts_all_hashes:
            raise self.skipTest("not applicable")
        if not self.known_other_hashes:
            raise self.skipTest("no foreign hashes provided")
        for name, hash in self.known_other_hashes:
            # NOTE: most tests use default list of foreign hashes,
            # so they may include ones belonging to that hash...
            # hence the 'own' logic.

            if name == self.handler.name:
                # identify should accept these
                self.assertTrue(self.do_identify(hash),
                    "identify() failed to identify known hash: %r" % (hash,))

                # verify & genhash should NOT throw error
                self.do_verify('stub', hash)
                result = self.do_genhash('stub', hash)
                self.assertIsInstance(result, str,
                    "genhash() failed to return native string: %r" % (result,))

            else:
                # identify should reject these
                self.assertFalse(self.do_identify(hash),
                    "identify() incorrectly identified hash belonging to "
                    "%s: %r" % (name, hash))

                # verify should throw error
                self.assertRaises(ValueError, self.do_verify, 'stub', hash,
                    __msg__= "verify() failed to throw error for hash "
                    "belonging to %s: %r" % (name, hash,))

                # genhash() should throw error
                self.assertRaises(ValueError, self.do_genhash, 'stub', hash,
                    __msg__= "genhash() failed to throw error for hash "
                    "belonging to %s: %r" % (name, hash))

    def test_76_none(self):
        "test empty hashes"
        #
        # test hash=None
        #
        # FIXME: allowing value or type error to simplify implementation,
        # but TypeError is really the correct one here.
        self.assertFalse(self.do_identify(None))
        self.assertRaises((ValueError, TypeError), self.do_verify, 'stub', None)
        if self.supports_config_string:
            self.assertRaises((ValueError, TypeError), self.do_genhash,
                'stub', None)
        else:
            result = self.do_genhash('stub', None)
            self.assertIsInstance(result, str,
                "genhash() failed to return native string: %r" % (result,))

        #
        # test hash=''
        #
        for hash in [u(''), b('')]:
            if self.accepts_all_hashes:
                # then it accepts empty string as well.
                self.assertTrue(self.do_identify(hash))
                self.do_verify('stub', hash)
                result = self.do_genhash('stub', hash)
                self.assertIsInstance(result, str,
                    "genhash() failed to return native string: %r" % (result,))
            else:
                self.assertFalse(self.do_identify(hash),
                    "identify() incorrectly identified empty hash")
                self.assertRaises(ValueError, self.do_verify, 'stub', hash,
                    __msg__="verify() failed to reject empty hash")
                self.assertRaises(ValueError, self.do_genhash, 'stub', hash,
                    __msg__="genhash() failed to reject empty hash")

    #---------------------------------------------------------
    # fuzz testing
    #---------------------------------------------------------
    """the following attempts to perform some basic fuzz testing
    of the handler, based on whatever information can be found about it.
    it does as much as it can within a fixed amount of time
    (defaults to 1 second, but can be overridden via $PASSLIB_TESTS_FUZZ_TIME).
    it tests the following:

    * randomly generated passwords including extended unicode chars
    * randomly selected rounds values (if rounds supported)
    * randomly selected salt sizes (if salts supported)
    * randomly selected identifiers (if multiple found)

    * runs output of selected backend against other available backends
      (if any) to detect errors occurring between different backends.
    * runs output against other "external" verifiers such as OS crypt()
    """

    fuzz_password_alphabet = u('qwertyASDF1234<>.@*#! \u00E1\u0259\u0411\u2113')
    fuzz_password_encoding = "utf-8"
    fuzz_settings = ["rounds", "salt_size", "ident"]

    def test_77_fuzz_input(self):
        """test random passwords and options"""
        if self.is_disabled_handler:
            raise self.skipTest("not applicable")

        # gather info
        from passlib.utils import tick
        handler = self.handler
        disabled = self.is_disabled_handler
        max_time = int(os.environ.get("PASSLIB_TESTS_FUZZ_TIME") or 1)
        verifiers = self.get_fuzz_verifiers()
        def vname(v):
            return (v.__doc__ or v.__name__).splitlines()[0]

        # do as many tests as possible for max_time seconds
        stop = tick() + max_time
        count = 0
        while tick() <= stop:
            # generate random password & options
            secret = self.get_fuzz_password()
            other = secret.strip()[1:]
            if rng.randint(0,1):
                secret = secret.encode(self.fuzz_password_encoding)
                other = other.encode(self.fuzz_password_encoding)
            kwds = self.get_fuzz_settings()
            ctx = dict((k,kwds[k]) for k in handler.context_kwds if k in kwds)

            # create new hash
            hash = self.do_encrypt(secret, **kwds)
            ##log.debug("fuzz test: hash=%r secret=%r", hash, secret)

            # run through all verifiers we found.
            for verify in verifiers:
                name = vname(verify)

                if not verify(secret, hash, **ctx):
                    raise self.failureException("failed to verify against %s: "
                                                "secret=%r config=%r hash=%r" %
                                                (name, secret, kwds, hash))
                # occasionally check that some other secret WON'T verify
                # against this hash.
                if rng.random() < .1 and verify(other, hash, **ctx):
                    raise self.failureException("was able to verify wrong "
                        "password using %s: wrong_secret=%r real_secret=%r "
                        "config=%r hash=%r" % (name, other, secret, kwds, hash))
            count +=1

        name = self.case_prefix
        if not isinstance(name, str):
            name = name()
        log.debug("fuzz test: %r checked %d passwords against %d verifiers (%s)",
                  name,  count, len(verifiers),
                  ", ".join(vname(v) for v in verifiers))

    def get_fuzz_verifiers(self):
        """return list of password verifiers (including external libs)

        used by fuzz testing.
        verifiers should be callable with signature
        ``func(password: unicode, hash: ascii str) -> ok: bool``.
        """
        handler = self.handler
        verifiers = []

        # test against self
        def check_default(secret, hash, **ctx):
            "self"
            return self.do_verify(secret, hash, **ctx)
        verifiers.append(check_default)

        # test against any other available backends
        if hasattr(handler, "backends") and enable_option("all-backends"):
            def maker(backend):
                def func(secret, hash):
                    with temporary_backend(handler, backend):
                        return handler.verify(secret, hash)
                func.__name__ = "check_" + backend + "_backend"
                func.__doc__ = backend + "-backend"
                return func
            cur = handler.get_backend()
            check_default.__doc__ = cur + "-backend"
            for backend in handler.backends:
                if backend != cur and handler.has_backend(backend):
                    verifiers.append(maker(backend))

        # test againt OS crypt()
        # NOTE: skipping this if using_patched_crypt since _has_crypt_support()
        # will return false positive in that case.
        if not self.using_patched_crypt and _has_crypt_support(handler):
            from crypt import crypt
            def check_crypt(secret, hash):
                "stdlib-crypt"
                secret = to_native_str(secret, self.fuzz_password_encoding)
                return crypt(secret, hash) == hash
            verifiers.append(check_crypt)

        return verifiers

    def get_fuzz_password(self):
        "generate random passwords (for fuzz testing)"
        return getrandstr(rng, self.fuzz_password_alphabet, rng.randint(5,15))

    def get_fuzz_settings(self):
        "generate random settings (for fuzz testing)"
        kwds = {}
        for name in self.fuzz_settings:
            func = getattr(self, "get_fuzz_" + name)
            value = func()
            if value is not None:
                kwds[name] = value
        return kwds

    def get_fuzz_rounds(self):
        handler = self.handler
        if not has_rounds_info(handler):
            return None
        default = handler.default_rounds or handler.min_rounds
        if handler.rounds_cost == "log2":
            lower = max(default-1, handler.min_rounds)
            upper = default
        else:
            lower = handler.min_rounds #max(default*.5, handler.min_rounds)
            upper = min(default*2, handler.max_rounds)
        return randintgauss(lower, upper, default, default*.5)

    def get_fuzz_salt_size(self):
        handler = self.handler
        if not (has_salt_info(handler) and 'salt_size' in handler.setting_kwds):
            return None
        default = handler.default_salt_size
        lower = handler.min_salt_size
        upper = handler.max_salt_size or default*4
        return randintgauss(lower, upper, default, default*.5)

    def get_fuzz_ident(self):
        handler = self.handler
        if 'ident' in handler.setting_kwds and hasattr(handler, "ident_values"):
            if rng.random() < .5:
                return rng.choice(handler.ident_values)

    #=========================================================
    # test 8x - mixin tests
    # test 9x - handler-specific tests
    #=========================================================

    #=========================================================
    # eoc
    #=========================================================

class UserHandlerMixin(HandlerCase):
    """helper for handlers w/ 'user' context kwd; mixin for HandlerCase

    this overrides the HandlerCase test harness methods
    so that a username is automatically inserted to encrypt/verify
    calls. as well, passing in a pair of strings as the password
    will be interpreted as (secret,user)
    """
    __unittest_skip = True
    default_user = "user"
    user_case_insensitive = False

    def test_80_user(self):
        "test user context keyword"
        handler = self.handler
        password = 'stub'
        hash = self.get_sample_hash()[1]

        handler.encrypt(password, u('user'))

        self.assertRaises(TypeError, handler.encrypt, password)
        self.assertRaises(TypeError, handler.genhash, password, hash)
        self.assertRaises(TypeError, handler.verify, password, hash)

    # TODO: user size? kinda dicey, depends on algorithm.

    def test_81_user_case(self):
        "test user case sensitivity"
        lower = (self.default_user or 'user').lower()
        upper = lower.upper()
        hash = self.do_encrypt('stub', user=lower)
        if self.user_case_insensitive:
            self.assertTrue(self.do_verify('stub', hash, user=upper),
                            "user should not be case sensitive")
        else:
            self.assertFalse(self.do_verify('stub', hash, user=upper),
                             "user should be case sensitive")

    def is_secret_8bit(self, secret):
        secret = self._insert_user({}, secret)
        return not is_ascii_safe(secret)

    def _insert_user(self, kwds, secret):
        "insert username into kwds"
        if isinstance(secret, tuple):
            secret, user = secret
        else:
            user = self.default_user
        if 'user' not in kwds:
            kwds['user'] = user
        return secret

    def do_encrypt(self, secret, **kwds):
        secret = self._insert_user(kwds, secret)
        return self.handler.encrypt(secret, **kwds)

    def do_verify(self, secret, hash, **kwds):
        secret = self._insert_user(kwds, secret)
        return self.handler.verify(secret, hash, **kwds)

    def do_genhash(self, secret, config, **kwds):
        secret = self._insert_user(kwds, secret)
        return self.handler.genhash(secret, config, **kwds)

    fuzz_user_alphabet = u("asdQWE123")
    fuzz_settings = HandlerCase.fuzz_settings + ["user"]
    def get_fuzz_user(self):
        return getrandstr(rng, self.fuzz_user_alphabet, rng.randint(2,10))

#=========================================================
#backend test helpers
#=========================================================
def _enable_backend_case(handler, backend):
    "helper to check if testcase should be enabled for the specified backend"
    assert backend in handler.backends, "unknown backend: %r" % (backend,)
    if enable_option("all-backends") or _is_default_backend(handler, backend):
        if handler.has_backend(backend):
            return True, None
        from passlib.utils import has_crypt
        if backend == "os_crypt" and has_crypt:
            if enable_option("cover") and _has_other_backends(handler, "os_crypt"):
                #in this case, HandlerCase will monkeypatch os_crypt
                #to use another backend, just so we can test os_crypt fully.
                return True, None
            else:
                return False, "hash not supported by os crypt()"
        else:
            return False, "backend not available"
    else:
        return False, "only default backend being tested"

def _is_default_backend(handler, name):
    "check if backend is the default for handler"
    try:
        orig = handler.get_backend()
    except MissingBackendError:
        return False
    try:
        return handler.set_backend("default") == name
    finally:
        handler.set_backend(orig)

def _has_other_backends(handler, ignore):
    "helper to check if alternate backend is available"
    for name in handler.backends:
        if name != ignore and handler.has_backend(name):
            return name
    return None

def _has_crypt_support(handler):
    "check if host OS' crypt() supports this natively"
    # ignore wrapper classes
    if hasattr(handler, "orig_prefix"):
        return False
    # os crypt support?
    return hasattr(handler, "backends") and \
        'os_crypt' in handler.backends and \
        handler.has_backend("os_crypt")

def _has_relaxed_setting(handler):
    # FIXME: I've been lazy, should probably just add 'relaxed' kwd
    # to all handlers that derive from GenericHandler

    # ignore wrapper classes for now.. though could introspec.
    if hasattr(handler, "orig_prefix"):
        return False

    return 'relaxed' in handler.setting_kwds or issubclass(handler,
                                                           uh.GenericHandler)

def _hobj_to_dict(hobj):
    "hack to convert handler instance to dict"
    # FIXME: would be good to distinguish config-string keywords
    # from generation options (e.g. salt size) in programmatic manner.
    exclude_keys = ["salt_size", "relaxed"]
    return dict(
        (key, getattr(hobj, key))
        for key in hobj.setting_kwds
        if key not in exclude_keys
    )

def create_backend_case(base, name, module="passlib.tests.test_handlers"):
    "create a test case for specific backend of a multi-backend handler"
    #get handler, figure out if backend should be tested
    handler = base.handler
    assert hasattr(handler, "backends"), "handler must support uh.HasManyBackends protocol"
    enable, reason = _enable_backend_case(handler, name)

    #UT1 doesn't support skipping whole test cases,
    #so we just return None.
    if not enable and ut_version < 2:
        return None

    #make classname match what it's stored under, to be tidy
    cname = name.title().replace("_","") + "_" + base.__name__.lstrip("_")

    #create subclass of 'base' which uses correct backend
    subcase = type(
        cname,
        (base,),
        dict(
            case_prefix = "%s (%s backend)" % (handler.name, name),
            backend = name,
            __module__=module,
        )
    )

    if not enable:
        subcase = unittest.skip(reason)(subcase)

    return subcase

#=========================================================
#misc helpers
#=========================================================
def limit(value, lower, upper):
    if value < lower:
        return lower
    elif value > upper:
        return upper
    return value

def randintgauss(lower, upper, mu, sigma):
    "hack used by fuzz testing"
    return int(limit(rng.normalvariate(mu, sigma), lower, upper))

class temporary_backend(object):
    "temporarily set handler to specific backend"
    def __init__(self, handler, backend=None):
        self.handler = handler
        self.backend = backend

    def __enter__(self):
        orig = self._orig = self.handler.get_backend()
        if self.backend:
            self.handler.set_backend(self.backend)
        return orig

    def __exit__(self, *exc_info):
        registry._unload_handler_name(self.name, locations=False)

#=========================================================
#helper for creating temp files - all cleaned up when prog exits
#=========================================================
tmp_files = []

def _clean_tmp_files():
    for path in tmp_files:
        if os.path.exists(path):
            os.remove(path)
atexit.register(_clean_tmp_files)

def mktemp(*args, **kwds):
    fd, path = tempfile.mkstemp(*args, **kwds)
    tmp_files.append(path)
    os.close(fd)
    return path

#=========================================================
#make sure catch_warnings() is available
#=========================================================
try:
    from warnings import catch_warnings
except ImportError:
    #catch_warnings wasn't added until py26.
    #this adds backported copy from py26's stdlib
    #so we can use it under py25.

    class WarningMessage(object):

        """Holds the result of a single showwarning() call."""

        _WARNING_DETAILS = ("message", "category", "filename", "lineno", "file",
                            "line")

        def __init__(self, message, category, filename, lineno, file=None,
                        line=None):
            local_values = locals()
            for attr in self._WARNING_DETAILS:
                setattr(self, attr, local_values[attr])
            self._category_name = category.__name__ if category else None

        def __str__(self):
            return ("{message : %r, category : %r, filename : %r, lineno : %s, "
                        "line : %r}" % (self.message, self._category_name,
                                        self.filename, self.lineno, self.line))


    class catch_warnings(object):

        """A context manager that copies and restores the warnings filter upon
        exiting the context.

        The 'record' argument specifies whether warnings should be captured by a
        custom implementation of warnings.showwarning() and be appended to a list
        returned by the context manager. Otherwise None is returned by the context
        manager. The objects appended to the list are arguments whose attributes
        mirror the arguments to showwarning().

        The 'module' argument is to specify an alternative module to the module
        named 'warnings' and imported under that name. This argument is only useful
        when testing the warnings module itself.

        """

        def __init__(self, record=False, module=None):
            """Specify whether to record warnings and if an alternative module
            should be used other than sys.modules['warnings'].

            For compatibility with Python 3.0, please consider all arguments to be
            keyword-only.

            """
            self._record = record
            self._module = sys.modules['warnings'] if module is None else module
            self._entered = False

        def __repr__(self):
            args = []
            if self._record:
                args.append("record=True")
            if self._module is not sys.modules['warnings']:
                args.append("module=%r" % self._module)
            name = type(self).__name__
            return "%s(%s)" % (name, ", ".join(args))

        def __enter__(self):
            if self._entered:
                raise RuntimeError("Cannot enter %r twice" % self)
            self._entered = True
            self._filters = self._module.filters
            self._module.filters = self._filters[:]
            self._showwarning = self._module.showwarning
            if self._record:
                log = []
                def showwarning(*args, **kwargs):
#                    self._showwarning(*args, **kwargs)
                    log.append(WarningMessage(*args, **kwargs))
                self._module.showwarning = showwarning
                return log
            else:
                return None

        def __exit__(self, *exc_info):
            if not self._entered:
                raise RuntimeError("Cannot exit %r without entering first" % self)
            self._module.filters = self._filters
            self._module.showwarning = self._showwarning

#=========================================================
#EOF
#=========================================================