source: python/trunk/Lib/test/test_xpickle.py

# test_pickle dumps and loads pickles via pickle.py.
# test_cpickle does the same, but via the cPickle module.
# This test covers the other two cases, making pickles with one module and
# loading them via the other. It also tests backwards compatibility with
# previous version of Python by bouncing pickled objects through Python 2.4
# and Python 2.5 running this file.

import cPickle
import os
import os.path
import pickle
import subprocess
import sys
import types
import unittest

from test import test_support

# Most distro-supplied Pythons don't include the tests
# or test support files, and some don't include a way to get these back even if
# you're will to install extra packages (like Ubuntu). Doing things like this
# "provides" a pickletester module for older versions of Python that may be
# installed without it. Note that one other design for this involves messing
# with sys.path, which is less precise.
mod_path = os.path.abspath(os.path.join(os.path.dirname(__file__),
                                        "pickletester.py"))
pickletester = types.ModuleType("test.pickletester")
exec compile(open(mod_path).read(), mod_path, 'exec') in pickletester.__dict__
AbstractPickleTests = pickletester.AbstractPickleTests
if pickletester.__name__ in sys.modules:
    raise RuntimeError("Did not expect to find test.pickletester loaded")
sys.modules[pickletester.__name__] = pickletester


class DumpCPickle_LoadPickle(AbstractPickleTests):

    error = KeyError

    def dumps(self, arg, proto=0, fast=False):
        # Ignore fast
        return cPickle.dumps(arg, proto)

    def loads(self, buf):
        # Ignore fast
        return pickle.loads(buf)

class DumpPickle_LoadCPickle(AbstractPickleTests):

    error = cPickle.BadPickleGet

    def dumps(self, arg, proto=0, fast=False):
        # Ignore fast
        return pickle.dumps(arg, proto)

    def loads(self, buf):
        # Ignore fast
        return cPickle.loads(buf)

def have_python_version(name):
    """Check whether the given name is a valid Python binary and has
    test.test_support.

    This respects your PATH.

    Args:
        name: short string name of a Python binary such as "python2.4".

    Returns:
        True if the name is valid, False otherwise.
    """
    return os.system(name + " -c 'import test.test_support'") == 0


class AbstractCompatTests(AbstractPickleTests):

    module = None
    python = None
    error = None

    def setUp(self):
        self.assertTrue(self.python)
        self.assertTrue(self.module)
        self.assertTrue(self.error)

    def send_to_worker(self, python, obj, proto):
        """Bounce a pickled object through another version of Python.

        This will pickle the object, send it to a child process where it will be
        unpickled, then repickled and sent back to the parent process.

        Args:
            python: the name of the Python binary to start.
            obj: object to pickle.
            proto: pickle protocol number to use.

        Returns:
            The pickled data received from the child process.
        """
        # Prevent the subprocess from picking up invalid .pyc files.
        target = __file__
        if target[-1] in ("c", "o"):
            target = target[:-1]

        data = self.module.dumps((proto, obj), proto)
        worker = subprocess.Popen([python, target, "worker"],
                                  stdin=subprocess.PIPE,
                                  stdout=subprocess.PIPE,
                                  stderr=subprocess.PIPE)
        stdout, stderr = worker.communicate(data)
        if worker.returncode != 0:
            raise RuntimeError(stderr)
        return stdout

    def dumps(self, arg, proto=0, fast=False):
        return self.send_to_worker(self.python, arg, proto)

    def loads(self, input):
        return self.module.loads(input)

    # These tests are disabled because they require some special setup
    # on the worker that's hard to keep in sync.
    def test_global_ext1(self):
        pass

    def test_global_ext2(self):
        pass

    def test_global_ext4(self):
        pass

    # This is a cut-down version of pickletester's test_float. Backwards
    # compatibility for the values in for_bin_protos was explicitly broken in
    # r68903 to fix a bug.
    def test_float(self):
        for_bin_protos = [4.94e-324, 1e-310]
        neg_for_bin_protos = [-x for x in for_bin_protos]
        test_values = [0.0, 7e-308, 6.626e-34, 0.1, 0.5,
                       3.14, 263.44582062374053, 6.022e23, 1e30]
        test_proto0_values = test_values + [-x for x in test_values]
        test_values = test_proto0_values + for_bin_protos + neg_for_bin_protos

        for value in test_proto0_values:
            pickle = self.dumps(value, 0)
            got = self.loads(pickle)
            self.assertEqual(value, got)

        for proto in pickletester.protocols[1:]:
            for value in test_values:
                pickle = self.dumps(value, proto)
                got = self.loads(pickle)
                self.assertEqual(value, got)

    # Backwards compatibility was explicitly broken in r67934 to fix a bug.
    def test_unicode_high_plane(self):
        pass

    # This tests a fix that's in 2.7 only
    def test_dynamic_class(self):
        pass

    if test_support.have_unicode:
        # This is a cut-down version of pickletester's test_unicode. Backwards
        # compatibility was explicitly broken in r67934 to fix a bug.
        def test_unicode(self):
            endcases = [u'', u'<\\u>', u'<\\\u1234>', u'<\n>', u'<\\>']
            for proto in pickletester.protocols:
                for u in endcases:
                    p = self.dumps(u, proto)
                    u2 = self.loads(p)
                    self.assertEqual(u2, u)


def run_compat_test(python_name):
    return (test_support.is_resource_enabled("xpickle") and
            have_python_version(python_name))


# Test backwards compatibility with Python 2.4.
if not run_compat_test("python2.4"):
    class CPicklePython24Compat(unittest.TestCase):
        pass
else:
    class CPicklePython24Compat(AbstractCompatTests):

        module = cPickle
        python = "python2.4"
        error = cPickle.BadPickleGet

        # Disable these tests for Python 2.4. Making them pass would require
        # nontrivially monkeypatching the pickletester module in the worker.
        def test_reduce_calls_base(self):
            pass

        def test_reduce_ex_calls_base(self):
            pass

class PicklePython24Compat(CPicklePython24Compat):

    module = pickle
    error = KeyError


# Test backwards compatibility with Python 2.5.
if not run_compat_test("python2.5"):
    class CPicklePython25Compat(unittest.TestCase):
        pass
else:
    class CPicklePython25Compat(AbstractCompatTests):

        module = cPickle
        python = "python2.5"
        error = cPickle.BadPickleGet

class PicklePython25Compat(CPicklePython25Compat):

    module = pickle
    error = KeyError


# Test backwards compatibility with Python 2.6.
if not run_compat_test("python2.6"):
    class CPicklePython26Compat(unittest.TestCase):
        pass
else:
    class CPicklePython26Compat(AbstractCompatTests):

        module = cPickle
        python = "python2.6"
        error = cPickle.BadPickleGet

class PicklePython26Compat(CPicklePython26Compat):

    module = pickle
    error = KeyError


def worker_main(in_stream, out_stream):
    message = cPickle.load(in_stream)
    protocol, obj = message
    cPickle.dump(obj, out_stream, protocol)


def test_main():
    if not test_support.is_resource_enabled("xpickle"):
        print >>sys.stderr, "test_xpickle -- skipping backwards compat tests."
        print >>sys.stderr, "Use 'regrtest.py -u xpickle' to run them."
        sys.stderr.flush()

    test_support.run_unittest(
        DumpCPickle_LoadPickle,
        DumpPickle_LoadCPickle,
        CPicklePython24Compat,
        CPicklePython25Compat,
        CPicklePython26Compat,
        PicklePython24Compat,
        PicklePython25Compat,
        PicklePython26Compat,
    )

if __name__ == "__main__":
    if "worker" in sys.argv:
        worker_main(sys.stdin, sys.stdout)
    else:
        test_main()