test_persistence.py

# (C) Copyright 2005-2024 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!


class Foo0:
    """ The original class written with no expectation of being upgraded """
    def __init__(self):
        self.prenom = 'didier'
        self.surnom = 'enfant'


class Foo1:
    """ Now to handle both Foo v0 and Foo v1 we need to add more code ..."""

    def __init__(self, firstname, lastname):
        """ This does not get called when the class is unpickled."""
        self.firstname = firstname
        self.lastname = lastname


class Foo:

    def __str__(self):
        result = ['----------------------------------------------------------']
        keys = dir(self)
        for key in keys:
            result.append('%s ---> %s' % (key, getattr(self, key)))
        result.append('------------------------------------------------------')
        return '\n'.join(result)

    def __setstate__(self, state):
        print('calling setstate on the real Foo')
        state['set'] = True
        self.__dict__.update(state)


def save(fname, str):
    f = open(fname, 'w')
    f.write(str)
    f.close()


if __name__ == '__main__':

    # Create dummy test data .......
    import pickle

    obj = Foo0()
    print(obj)
    t0 = pickle.dumps(obj)
    save('foo0.txt', t0)

    '''obj = Foo1('duncan', 'child')
    t1 = pickle.dumps(obj).replace('Foo1', 'Foo')
    save('foo1.txt', t1)

    obj = Foo2('duncan child')
    t2 = pickle.dumps(obj).replace('Foo2', 'Foo')
    save('foo2.txt', t2)

    obj = Foo3('duncan child')
    t3 = pickle.dumps(obj).replace('Foo3', 'Foo')
    save('foo3.txt', t3)
    '''

    print('==================================================================')

    from apptools.persistence.versioned_unpickler import VersionedUnpickler
    # Try and read them back in ...
    f = open('foo0.txt')

    import sys
    rev = 1
    __import__('integrationtests.persistence.update%d' % rev)
    mod = sys.modules['integrationtests.persistence.update%d' % rev]
    klass = getattr(mod, 'Update%d' % rev)
    updater = klass()
    print('%s %s' % (rev, updater))

    p = VersionedUnpickler(f, updater).load()
    print(p)
    print('Restored version %s %s' % (p.lastname, p.firstname))