Merged Trevor's tree

1 files changed, 1070 insertions, 0 deletions

diff --git a/libbe/storage/base.py b/libbe/storage/base.py
new file mode 100644
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+++ b/libbe/storage/base.py
@@ -0,0 +1,1070 @@
+# Copyright (C) 2009-2010 W. Trevor King <wking@drexel.edu>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+"""
+Abstract bug repository data storage to easily support multiple backends.
+"""
+
+import copy
+import os
+import pickle
+import types
+
+from libbe.error import NotSupported
+import libbe.storage
+from libbe.util.tree import Tree
+from libbe.util import InvalidObject
+import libbe.version
+from libbe import TESTING
+
+if TESTING == True:
+    import doctest
+    import os.path
+    import sys
+    import unittest
+
+    from libbe.util.utility import Dir
+
+class ConnectionError (Exception):
+    pass
+
+class InvalidStorageVersion(ConnectionError):
+    def __init__(self, active_version, expected_version=None):
+        if expected_version == None:
+            expected_version = libbe.storage.STORAGE_VERSION
+        msg = 'Storage in "%s" not the expected "%s"' \
+            % (active_version, expected_version)
+        Exception.__init__(self, msg)
+        self.active_version = active_version
+        self.expected_version = expected_version
+
+class InvalidID (KeyError):
+    def __init__(self, id=None, revision=None, msg=None):
+        KeyError.__init__(self, id)
+        self.msg = msg
+        self.id = id
+        self.revision = revision
+    def __str__(self):
+        if self.msg == None:
+            return '%s in revision %s' % (self.id, self.revision)
+        return self.msg
+
+
+class InvalidRevision (KeyError):
+    pass
+
+class InvalidDirectory (Exception):
+    pass
+
+class DirectoryNotEmpty (InvalidDirectory):
+    pass
+
+class NotWriteable (NotSupported):
+    def __init__(self, msg):
+        NotSupported.__init__(self, 'write', msg)
+
+class NotReadable (NotSupported):
+    def __init__(self, msg):
+        NotSupported.__init__(self, 'read', msg)
+
+class EmptyCommit(Exception):
+    def __init__(self):
+        Exception.__init__(self, 'No changes to commit')
+
+class _EMPTY (object):
+    """Entry has been added but has no user-set value."""
+    pass
+
+class Entry (Tree):
+    def __init__(self, id, value=_EMPTY, parent=None, directory=False,
+                 children=None):
+        if children == None:
+            Tree.__init__(self)
+        else:
+            Tree.__init__(self, children)
+        self.id = id
+        self.value = value
+        self.parent = parent
+        if self.parent != None:
+            if self.parent.directory == False:
+                raise InvalidDirectory(
+                    'Non-directory %s cannot have children' % self.parent)
+            parent.append(self)
+        self.directory = directory
+
+    def __str__(self):
+        return '<Entry %s: %s>' % (self.id, self.value)
+
+    def __repr__(self):
+        return str(self)
+
+    def __cmp__(self, other, local=False):
+        if other == None:
+            return cmp(1, None)
+        if cmp(self.id, other.id) != 0:
+            return cmp(self.id, other.id)
+        if cmp(self.value, other.value) != 0:
+            return cmp(self.value, other.value)
+        if local == False:
+            if self.parent == None:
+                if cmp(self.parent, other.parent) != 0:
+                    return cmp(self.parent, other.parent)
+            elif self.parent.__cmp__(other.parent, local=True) != 0:
+                return self.parent.__cmp__(other.parent, local=True)
+            for sc,oc in zip(self, other):
+                if sc.__cmp__(oc, local=True) != 0:
+                    return sc.__cmp__(oc, local=True)
+        return 0
+
+    def _objects_to_ids(self):
+        if self.parent != None:
+            self.parent = self.parent.id
+        for i,c in enumerate(self):
+            self[i] = c.id
+        return self
+
+    def _ids_to_objects(self, dict):
+        if self.parent != None:
+            self.parent = dict[self.parent]
+        for i,c in enumerate(self):
+            self[i] = dict[c]
+        return self
+
+class Storage (object):
+    """
+    This class declares all the methods required by a Storage
+    interface.  This implementation just keeps the data in a
+    dictionary and uses pickle for persistent storage.
+    """
+    name = 'Storage'
+
+    def __init__(self, repo='/', encoding='utf-8', options=None):
+        self.repo = repo
+        self.encoding = encoding
+        self.options = options
+        self.readable = True  # soft limit (user choice)
+        self._readable = True # hard limit (backend choice)
+        self.writeable = True  # soft limit (user choice)
+        self._writeable = True # hard limit (backend choice)
+        self.versioned = False
+        self.can_init = True
+        self.connected = False
+
+    def __str__(self):
+        return '<%s %s %s>' % (self.__class__.__name__, id(self), self.repo)
+
+    def __repr__(self):
+        return str(self)
+
+    def version(self):
+        """Return a version string for this backend."""
+        return libbe.version.version()
+
+    def storage_version(self, revision=None):
+        """Return the storage format for this backend."""
+        return libbe.storage.STORAGE_VERSION
+
+    def is_readable(self):
+        return self.readable and self._readable
+
+    def is_writeable(self):
+        return self.writeable and self._writeable
+
+    def init(self):
+        """Create a new storage repository."""
+        if self.can_init == False:
+            raise NotSupported('init',
+                               'Cannot initialize this repository format.')
+        if self.is_writeable() == False:
+            raise NotWriteable('Cannot initialize unwriteable storage.')
+        return self._init()
+
+    def _init(self):
+        f = open(os.path.join(self.repo, 'repo.pkl'), 'wb')
+        root = Entry(id='__ROOT__', directory=True)
+        d = {root.id:root}
+        pickle.dump(dict((k,v._objects_to_ids()) for k,v in d.items()), f, -1)
+        f.close()
+
+    def destroy(self):
+        """Remove the storage repository."""
+        if self.is_writeable() == False:
+            raise NotWriteable('Cannot destroy unwriteable storage.')
+        return self._destroy()
+
+    def _destroy(self):
+        os.remove(os.path.join(self.repo, 'repo.pkl'))
+
+    def connect(self):
+        """Open a connection to the repository."""
+        if self.is_readable() == False:
+            raise NotReadable('Cannot connect to unreadable storage.')
+        self._connect()
+        self.connected = True
+
+    def _connect(self):
+        try:
+            f = open(os.path.join(self.repo, 'repo.pkl'), 'rb')
+        except IOError:
+            raise ConnectionError(self)
+        d = pickle.load(f)
+        self._data = dict((k,v._ids_to_objects(d)) for k,v in d.items())
+        f.close()
+
+    def disconnect(self):
+        """Close the connection to the repository."""
+        if self.is_writeable() == False:
+            return
+        if self.connected == False:
+            return
+        self._disconnect()
+        self.connected = False
+
+    def _disconnect(self):
+        f = open(os.path.join(self.repo, 'repo.pkl'), 'wb')
+        pickle.dump(dict((k,v._objects_to_ids())
+                         for k,v in self._data.items()), f, -1)
+        f.close()
+        self._data = None
+
+    def add(self, id, *args, **kwargs):
+        """Add an entry"""
+        if self.is_writeable() == False:
+            raise NotWriteable('Cannot add entry to unwriteable storage.')
+        if not self.exists(id):
+            self._add(id, *args, **kwargs)
+
+    def _add(self, id, parent=None, directory=False):
+        if parent == None:
+            parent = '__ROOT__'
+        p = self._data[parent]
+        self._data[id] = Entry(id, parent=p, directory=directory)
+
+    def exists(self, *args, **kwargs):
+        """Check an entry's existence"""
+        if self.is_readable() == False:
+            raise NotReadable('Cannot check entry existence in unreadable storage.')
+        return self._exists(*args, **kwargs)
+
+    def _exists(self, id, revision=None):
+        return id in self._data
+
+    def remove(self, *args, **kwargs):
+        """Remove an entry."""
+        if self.is_writeable() == False:
+            raise NotSupported('write',
+                               'Cannot remove entry from unwriteable storage.')
+        self._remove(*args, **kwargs)
+
+    def _remove(self, id):
+        if self._data[id].directory == True \
+                and len(self.children(id)) > 0:
+            raise DirectoryNotEmpty(id)
+        e = self._data.pop(id)
+        e.parent.remove(e)
+
+    def recursive_remove(self, *args, **kwargs):
+        """Remove an entry and all its decendents."""
+        if self.is_writeable() == False:
+            raise NotSupported('write',
+                               'Cannot remove entries from unwriteable storage.')
+        self._recursive_remove(*args, **kwargs)
+
+    def _recursive_remove(self, id):
+        for entry in reversed(list(self._data[id].traverse())):
+            self._remove(entry.id)
+
+    def ancestors(self, *args, **kwargs):
+        """Return a list of the specified entry's ancestors' ids."""
+        if self.is_readable() == False:
+            raise NotReadable('Cannot list parents with unreadable storage.')
+        return self._ancestors(*args, **kwargs)
+
+    def _ancestors(self, id=None, revision=None):
+        if id == None:
+            return []
+        ancestors = []
+        stack = [id]
+        while len(stack) > 0:
+            id = stack.pop(0)
+            parent = self._data[id].parent
+            if parent != None and not parent.id.startswith('__'):
+                ancestor = parent.id
+                ancestors.append(ancestor)
+                stack.append(ancestor)
+        return ancestors
+
+    def children(self, *args, **kwargs):
+        """Return a list of specified entry's children's ids."""
+        if self.is_readable() == False:
+            raise NotReadable('Cannot list children with unreadable storage.')
+        return self._children(*args, **kwargs)
+
+    def _children(self, id=None, revision=None):
+        if id == None:
+            id = '__ROOT__'
+        return [c.id for c in self._data[id] if not c.id.startswith('__')]
+
+    def get(self, *args, **kwargs):
+        """
+        Get contents of and entry as they were in a given revision.
+        revision==None specifies the current revision.
+
+        If there is no id, return default, unless default is not
+        given, in which case raise InvalidID.
+        """
+        if self.is_readable() == False:
+            raise NotReadable('Cannot get entry with unreadable storage.')
+        if 'decode' in kwargs:
+            decode = kwargs.pop('decode')
+        else:
+            decode = False
+        value = self._get(*args, **kwargs)
+        if value != None:
+            if decode == True and type(value) != types.UnicodeType:
+                return unicode(value, self.encoding)
+            elif decode == False and type(value) != types.StringType:
+                return value.encode(self.encoding)
+        return value
+
+    def _get(self, id, default=InvalidObject, revision=None):
+        if id in self._data and self._data[id].value != _EMPTY:
+            return self._data[id].value
+        elif default == InvalidObject:
+            raise InvalidID(id)
+        return default
+
+    def set(self, id, value, *args, **kwargs):
+        """
+        Set the entry contents.
+        """
+        if self.is_writeable() == False:
+            raise NotWriteable('Cannot set entry in unwriteable storage.')
+        if type(value) == types.UnicodeType:
+            value = value.encode(self.encoding)
+        self._set(id, value, *args, **kwargs)
+
+    def _set(self, id, value):
+        if id not in self._data:
+            raise InvalidID(id)
+        if self._data[id].directory == True:
+            raise InvalidDirectory(
+                'Directory %s cannot have data' % self.parent)
+        self._data[id].value = value
+
+class VersionedStorage (Storage):
+    """
+    This class declares all the methods required by a Storage
+    interface that supports versioning.  This implementation just
+    keeps the data in a list and uses pickle for persistent
+    storage.
+    """
+    name = 'VersionedStorage'
+
+    def __init__(self, *args, **kwargs):
+        Storage.__init__(self, *args, **kwargs)
+        self.versioned = True
+
+    def _init(self):
+        f = open(os.path.join(self.repo, 'repo.pkl'), 'wb')
+        root = Entry(id='__ROOT__', directory=True)
+        summary = Entry(id='__COMMIT__SUMMARY__', value='Initial commit')
+        body = Entry(id='__COMMIT__BODY__')
+        initial_commit = {root.id:root, summary.id:summary, body.id:body}
+        d = dict((k,v._objects_to_ids()) for k,v in initial_commit.items())
+        pickle.dump([d, copy.deepcopy(d)], f, -1) # [inital tree, working tree]
+        f.close()
+
+    def _connect(self):
+        try:
+            f = open(os.path.join(self.repo, 'repo.pkl'), 'rb')
+        except IOError:
+            raise ConnectionError(self)
+        d = pickle.load(f)
+        self._data = [dict((k,v._ids_to_objects(t)) for k,v in t.items())
+                      for t in d]
+        f.close()
+
+    def _disconnect(self):
+        f = open(os.path.join(self.repo, 'repo.pkl'), 'wb')
+        pickle.dump([dict((k,v._objects_to_ids())
+                          for k,v in t.items()) for t in self._data], f, -1)
+        f.close()
+        self._data = None
+
+    def _add(self, id, parent=None, directory=False):
+        if parent == None:
+            parent = '__ROOT__'
+        p = self._data[-1][parent]
+        self._data[-1][id] = Entry(id, parent=p, directory=directory)
+
+    def _exists(self, id, revision=None):
+        if revision == None:
+            revision = -1
+        else:
+            revision = int(revision)
+        return id in self._data[revision]
+
+    def _remove(self, id):
+        if self._data[-1][id].directory == True \
+                and len(self.children(id)) > 0:
+            raise DirectoryNotEmpty(id)
+        e = self._data[-1].pop(id)
+        e.parent.remove(e)
+
+    def _recursive_remove(self, id):
+        for entry in reversed(list(self._data[-1][id].traverse())):
+            self._remove(entry.id)
+
+    def _ancestors(self, id=None, revision=None):
+        if id == None:
+            return []
+        if revision == None:
+            revision = -1
+        else:
+            revision = int(revision)
+        ancestors = []
+        stack = [id]
+        while len(stack) > 0:
+            id = stack.pop(0)
+            parent = self._data[revision][id].parent
+            if parent != None and not parent.id.startswith('__'):
+                ancestor = parent.id
+                ancestors.append(ancestor)
+                stack.append(ancestor)
+        return ancestors
+
+    def _children(self, id=None, revision=None):
+        if id == None:
+            id = '__ROOT__'
+        if revision == None:
+            revision = -1
+        else:
+            revision = int(revision)
+        return [c.id for c in self._data[revision][id]
+                if not c.id.startswith('__')]
+
+    def _get(self, id, default=InvalidObject, revision=None):
+        if revision == None:
+            revision = -1
+        else:
+            revision = int(revision)
+        if id in self._data[revision] \
+                and self._data[revision][id].value != _EMPTY:
+            return self._data[revision][id].value
+        elif default == InvalidObject:
+            raise InvalidID(id)
+        return default
+
+    def _set(self, id, value):
+        if id not in self._data[-1]:
+            raise InvalidID(id)
+        self._data[-1][id].value = value
+
+    def commit(self, *args, **kwargs):
+        """
+        Commit the current repository, with a commit message string
+        summary and body.  Return the name of the new revision.
+
+        If allow_empty == False (the default), raise EmptyCommit if
+        there are no changes to commit.
+        """
+        if self.is_writeable() == False:
+            raise NotWriteable('Cannot commit to unwriteable storage.')
+        return self._commit(*args, **kwargs)
+
+    def _commit(self, summary, body=None, allow_empty=False):
+        if self._data[-1] == self._data[-2] and allow_empty == False:
+            raise EmptyCommit
+        self._data[-1]["__COMMIT__SUMMARY__"].value = summary
+        self._data[-1]["__COMMIT__BODY__"].value = body
+        rev = str(len(self._data)-1)
+        self._data.append(copy.deepcopy(self._data[-1]))
+        return rev
+
+    def revision_id(self, index=None):
+        """
+        Return the name of the <index>th revision.  The choice of
+        which branch to follow when crossing branches/merges is not
+        defined.  Revision indices start at 1; ID 0 is the blank
+        repository.
+
+        Return None if index==None.
+
+        If the specified revision does not exist, raise InvalidRevision.
+        """
+        if index == None:
+            return None
+        try:
+            if int(index) != index:
+                raise InvalidRevision(index)
+        except ValueError:
+            raise InvalidRevision(index)
+        L = len(self._data) - 1  # -1 b/c of initial commit
+        if index >= -L and index <= L:
+            return str(index % L)
+        raise InvalidRevision(i)
+
+    def changed(self, revision):
+        """Return a tuple of lists of ids `(new, modified, removed)` from the
+        specified revision to the current situation.
+        """
+        new = []
+        modified = []
+        removed = []
+        for id,value in self._data[int(revision)].items():
+            if id.startswith('__'):
+                continue
+            if not id in self._data[-1]:
+                removed.append(id)
+            elif value.value != self._data[-1][id].value:
+                modified.append(id)
+        for id in self._data[-1]:
+            if not id in self._data[int(revision)]:
+                new.append(id)
+        return (new, modified, removed)
+
+
+if TESTING == True:
+    class StorageTestCase (unittest.TestCase):
+        """Test cases for Storage class."""
+
+        Class = Storage
+
+        def __init__(self, *args, **kwargs):
+            super(StorageTestCase, self).__init__(*args, **kwargs)
+            self.dirname = None
+
+        # this class will be the basis of tests for several classes,
+        # so make sure we print the name of the class we're dealing with.
+        def _classname(self):
+            version = '?'
+            try:
+                if hasattr(self, 's'):
+                    version = self.s.version()
+            except:
+                pass
+            return '%s:%s' % (self.Class.__name__, version)
+
+        def fail(self, msg=None):
+            """Fail immediately, with the given message."""
+            raise self.failureException, \
+                '(%s) %s' % (self._classname(), msg)
+
+        def failIf(self, expr, msg=None):
+            "Fail the test if the expression is true."
+            if expr: raise self.failureException, \
+                '(%s) %s' % (self._classname(), msg)
+
+        def failUnless(self, expr, msg=None):
+            """Fail the test unless the expression is true."""
+            if not expr: raise self.failureException, \
+                '(%s) %s' % (self._classname(), msg)
+
+        def setUp(self):
+            """Set up test fixtures for Storage test case."""
+            super(StorageTestCase, self).setUp()
+            self.dir = Dir()
+            self.dirname = self.dir.path
+            self.s = self.Class(repo=self.dirname)
+            self.assert_failed_connect()
+            self.s.init()
+            self.s.connect()
+
+        def tearDown(self):
+            super(StorageTestCase, self).tearDown()
+            self.s.disconnect()
+            self.s.destroy()
+            self.assert_failed_connect()
+            self.dir.cleanup()
+
+        def assert_failed_connect(self):
+            try:
+                self.s.connect()
+                self.fail(
+                    "Connected to %(name)s repository before initialising"
+                    % vars(self.Class))
+            except ConnectionError:
+                pass
+
+    class Storage_init_TestCase (StorageTestCase):
+        """Test cases for Storage.init method."""
+
+        def test_connect_should_succeed_after_init(self):
+            """Should connect after initialization."""
+            self.s.connect()
+
+    class Storage_connect_disconnect_TestCase (StorageTestCase):
+        """Test cases for Storage.connect and .disconnect methods."""
+
+        def test_multiple_disconnects(self):
+            """Should be able to call .disconnect multiple times."""
+            self.s.disconnect()
+            self.s.disconnect()
+
+    class Storage_add_remove_TestCase (StorageTestCase):
+        """Test cases for Storage.add, .remove, and .recursive_remove methods."""
+
+        def test_initially_empty(self):
+            """New repository should be empty."""
+            self.failUnless(len(self.s.children()) == 0, self.s.children())
+
+        def test_add_identical_rooted(self):
+            """Adding entries with the same ID should not increase the number of children.
+            """
+            for i in range(10):
+                self.s.add('some id', directory=False)
+                s = sorted(self.s.children())
+                self.failUnless(s == ['some id'], s)
+
+        def test_add_rooted(self):
+            """Adding entries should increase the number of children (rooted).
+            """
+            ids = []
+            for i in range(10):
+                ids.append(str(i))
+                self.s.add(ids[-1], directory=(i % 2 == 0))
+                s = sorted(self.s.children())
+                self.failUnless(s == ids, '\n  %s\n  !=\n  %s' % (s, ids))
+
+        def test_add_nonrooted(self):
+            """Adding entries should increase the number of children (nonrooted).
+            """
+            self.s.add('parent', directory=True)
+            ids = []
+            for i in range(10):
+                ids.append(str(i))
+                self.s.add(ids[-1], 'parent', directory=(i % 2 == 0))
+                s = sorted(self.s.children('parent'))
+                self.failUnless(s == ids, '\n  %s\n  !=\n  %s' % (s, ids))
+                s = self.s.children()
+                self.failUnless(s == ['parent'], s)
+
+        def test_ancestors(self):
+            """Check ancestors lists.
+            """
+            self.s.add('parent', directory=True)
+            for i in range(10):
+                i_id = str(i)
+                self.s.add(i_id, 'parent', directory=True)
+                for j in range(10): # add some grandkids
+                    j_id = str(20*(i+1)+j)
+                    self.s.add(j_id, i_id, directory=(i%2 == 0))
+                    ancestors = sorted(self.s.ancestors(j_id))
+                    self.failUnless(ancestors == [i_id, 'parent'],
+                        'Unexpected ancestors for %s/%s, "%s"'
+                        % (i_id, j_id, ancestors))
+
+        def test_children(self):
+            """Non-UUID ids should be returned as such.
+            """
+            self.s.add('parent', directory=True)
+            ids = []
+            for i in range(10):
+                ids.append('parent/%s' % str(i))
+                self.s.add(ids[-1], 'parent', directory=(i % 2 == 0))
+                s = sorted(self.s.children('parent'))
+                self.failUnless(s == ids, '\n  %s\n  !=\n  %s' % (s, ids))
+
+        def test_add_invalid_directory(self):
+            """Should not be able to add children to non-directories.
+            """
+            self.s.add('parent', directory=False)
+            try:
+                self.s.add('child', 'parent', directory=False)
+                self.fail(
+                    '%s.add() succeeded instead of raising InvalidDirectory'
+                    % (vars(self.Class)['name']))
+            except InvalidDirectory:
+                pass
+            try:
+                self.s.add('child', 'parent', directory=True)
+                self.fail(
+                    '%s.add() succeeded instead of raising InvalidDirectory'
+                    % (vars(self.Class)['name']))
+            except InvalidDirectory:
+                pass
+            self.failUnless(len(self.s.children('parent')) == 0,
+                            self.s.children('parent'))
+
+        def test_remove_rooted(self):
+            """Removing entries should decrease the number of children (rooted).
+            """
+            ids = []
+            for i in range(10):
+                ids.append(str(i))
+                self.s.add(ids[-1], directory=(i % 2 == 0))
+            for i in range(10):
+                self.s.remove(ids.pop())
+                s = sorted(self.s.children())
+                self.failUnless(s == ids, '\n  %s\n  !=\n  %s' % (s, ids))
+
+        def test_remove_nonrooted(self):
+            """Removing entries should decrease the number of children (nonrooted).
+            """
+            self.s.add('parent', directory=True)
+            ids = []
+            for i in range(10):
+                ids.append(str(i))
+                self.s.add(ids[-1], 'parent', directory=False)#(i % 2 == 0))
+            for i in range(10):
+                self.s.remove(ids.pop())
+                s = sorted(self.s.children('parent'))
+                self.failUnless(s == ids, '\n  %s\n  !=\n  %s' % (s, ids))
+                if len(s) > 0:
+                    s = self.s.children()
+                    self.failUnless(s == ['parent'], s)
+
+        def test_remove_directory_not_empty(self):
+            """Removing a non-empty directory entry should raise exception.
+            """
+            self.s.add('parent', directory=True)
+            ids = []
+            for i in range(10):
+                ids.append(str(i))
+                self.s.add(ids[-1], 'parent', directory=(i % 2 == 0))
+            self.s.remove(ids.pop()) # empty directory removal succeeds
+            try:
+                self.s.remove('parent') # empty directory removal succeeds
+                self.fail(
+                    "%s.remove() didn't raise DirectoryNotEmpty"
+                    % (vars(self.Class)['name']))
+            except DirectoryNotEmpty:
+                pass
+
+        def test_recursive_remove(self):
+            """Recursive remove should empty the tree."""
+            self.s.add('parent', directory=True)
+            ids = []
+            for i in range(10):
+                ids.append(str(i))
+                self.s.add(ids[-1], 'parent', directory=True)
+                for j in range(10): # add some grandkids
+                    self.s.add(str(20*(i+1)+j), ids[-1], directory=(i%2 == 0))
+            self.s.recursive_remove('parent')
+            s = sorted(self.s.children())
+            self.failUnless(s == [], s)
+
+    class Storage_get_set_TestCase (StorageTestCase):
+        """Test cases for Storage.get and .set methods."""
+
+        id = 'unlikely id'
+        val = 'unlikely value'
+
+        def test_get_default(self):
+            """Get should return specified default if id not in Storage.
+            """
+            ret = self.s.get(self.id, default=self.val)
+            self.failUnless(ret == self.val,
+                    "%s.get() returned %s not %s"
+                    % (vars(self.Class)['name'], ret, self.val))
+
+        def test_get_default_exception(self):
+            """Get should raise exception if id not in Storage and no default.
+            """
+            try:
+                ret = self.s.get(self.id)
+                self.fail(
+                    "%s.get() returned %s instead of raising InvalidID"
+                    % (vars(self.Class)['name'], ret))
+            except InvalidID:
+                pass
+
+        def test_get_initial_value(self):
+            """Data value should be default before any value has been set.
+            """
+            self.s.add(self.id, directory=False)
+            val = 'UNLIKELY DEFAULT'
+            ret = self.s.get(self.id, default=val)
+            self.failUnless(ret == val,
+                    "%s.get() returned %s not %s"
+                    % (vars(self.Class)['name'], ret, val))
+
+        def test_set_exception(self):
+            """Set should raise exception if id not in Storage.
+            """
+            try:
+                self.s.set(self.id, self.val)
+                self.fail(
+                    "%(name)s.set() did not raise InvalidID"
+                    % vars(self.Class))
+            except InvalidID:
+                pass
+
+        def test_set(self):
+            """Set should define the value returned by get.
+            """
+            self.s.add(self.id, directory=False)
+            self.s.set(self.id, self.val)
+            ret = self.s.get(self.id)
+            self.failUnless(ret == self.val,
+                    "%s.get() returned %s not %s"
+                    % (vars(self.Class)['name'], ret, self.val))
+
+        def test_unicode_set(self):
+            """Set should define the value returned by get.
+            """
+            val = u'Fran\xe7ois'
+            self.s.add(self.id, directory=False)
+            self.s.set(self.id, val)
+            ret = self.s.get(self.id, decode=True)
+            self.failUnless(type(ret) == types.UnicodeType,
+                    "%s.get() returned %s not UnicodeType"
+                    % (vars(self.Class)['name'], type(ret)))
+            self.failUnless(ret == val,
+                    "%s.get() returned %s not %s"
+                    % (vars(self.Class)['name'], ret, self.val))
+            ret = self.s.get(self.id)
+            self.failUnless(type(ret) == types.StringType,
+                    "%s.get() returned %s not StringType"
+                    % (vars(self.Class)['name'], type(ret)))
+            s = unicode(ret, self.s.encoding)
+            self.failUnless(s == val,
+                    "%s.get() returned %s not %s"
+                    % (vars(self.Class)['name'], s, self.val))
+
+
+    class Storage_persistence_TestCase (StorageTestCase):
+        """Test cases for Storage.disconnect and .connect methods."""
+
+        id = 'unlikely id'
+        val = 'unlikely value'
+
+        def test_get_set_persistence(self):
+            """Set should define the value returned by get after reconnect.
+            """
+            self.s.add(self.id, directory=False)
+            self.s.set(self.id, self.val)
+            self.s.disconnect()
+            self.s.connect()
+            ret = self.s.get(self.id)
+            self.failUnless(ret == self.val,
+                    "%s.get() returned %s not %s"
+                    % (vars(self.Class)['name'], ret, self.val))
+
+        def test_empty_get_set_persistence(self):
+            """After empty set, get may return either an empty string or default.
+            """
+            self.s.add(self.id, directory=False)
+            self.s.set(self.id, '')
+            self.s.disconnect()
+            self.s.connect()
+            default = 'UNLIKELY DEFAULT'
+            ret = self.s.get(self.id, default=default)
+            self.failUnless(ret in ['', default],
+                    "%s.get() returned %s not in %s"
+                    % (vars(self.Class)['name'], ret, ['', default]))
+
+        def test_add_nonrooted_persistence(self):
+            """Adding entries should increase the number of children after reconnect.
+            """
+            self.s.add('parent', directory=True)
+            ids = []
+            for i in range(10):
+                ids.append(str(i))
+                self.s.add(ids[-1], 'parent', directory=(i % 2 == 0))
+            self.s.disconnect()
+            self.s.connect()
+            s = sorted(self.s.children('parent'))
+            self.failUnless(s == ids, '\n  %s\n  !=\n  %s' % (s, ids))
+            s = self.s.children()
+            self.failUnless(s == ['parent'], s)
+
+    class VersionedStorageTestCase (StorageTestCase):
+        """Test cases for VersionedStorage methods."""
+
+        Class = VersionedStorage
+
+    class VersionedStorage_commit_TestCase (VersionedStorageTestCase):
+        """Test cases for VersionedStorage.commit and revision_ids methods."""
+
+        id = 'unlikely id'
+        val = 'Some value'
+        commit_msg = 'Committing something interesting'
+        commit_body = 'Some\nlonger\ndescription\n'
+
+        def _setup_for_empty_commit(self):
+            """
+            Initialization might add some files to version control, so
+            commit those first, before testing the empty commit
+            functionality.
+            """
+            try:
+                self.s.commit('Added initialization files')
+            except EmptyCommit:
+                pass
+                
+        def test_revision_id_exception(self):
+            """Invalid revision id should raise InvalidRevision.
+            """
+            try:
+                rev = self.s.revision_id('highly unlikely revision id')
+                self.fail(
+                    "%s.revision_id() didn't raise InvalidRevision, returned %s."
+                    % (vars(self.Class)['name'], rev))
+            except InvalidRevision:
+                pass
+
+        def test_empty_commit_raises_exception(self):
+            """Empty commit should raise exception.
+            """
+            self._setup_for_empty_commit()
+            try:
+                self.s.commit(self.commit_msg, self.commit_body)
+                self.fail(
+                    "Empty %(name)s.commit() didn't raise EmptyCommit."
+                    % vars(self.Class))
+            except EmptyCommit:
+                pass
+
+        def test_empty_commit_allowed(self):
+            """Empty commit should _not_ raise exception if allow_empty=True.
+            """
+            self._setup_for_empty_commit()
+            self.s.commit(self.commit_msg, self.commit_body,
+                          allow_empty=True)
+
+        def test_commit_revision_ids(self):
+            """Commit / revision_id should agree on revision ids.
+            """
+            def val(i):
+                return '%s:%d' % (self.val, i+1)
+            self.s.add(self.id, directory=False)
+            revs = []
+            for i in range(10):
+                self.s.set(self.id, val(i))
+                revs.append(self.s.commit('%s: %d' % (self.commit_msg, i),
+                                          self.commit_body))
+            for i in range(10):
+                rev = self.s.revision_id(i+1)
+                self.failUnless(rev == revs[i],
+                                "%s.revision_id(%d) returned %s not %s"
+                                % (vars(self.Class)['name'], i+1, rev, revs[i]))
+            for i in range(-1, -9, -1):
+                rev = self.s.revision_id(i)
+                self.failUnless(rev == revs[i],
+                                "%s.revision_id(%d) returned %s not %s"
+                                % (vars(self.Class)['name'], i, rev, revs[i]))
+
+        def test_get_previous_version(self):
+            """Get should be able to return the previous version.
+            """
+            def val(i):
+                return '%s:%d' % (self.val, i+1)
+            self.s.add(self.id, directory=False)
+            revs = []
+            for i in range(10):
+                self.s.set(self.id, val(i))
+                revs.append(self.s.commit('%s: %d' % (self.commit_msg, i),
+                                          self.commit_body))
+            for i in range(10):
+                ret = self.s.get(self.id, revision=revs[i])
+                self.failUnless(ret == val(i),
+                                "%s.get() returned %s not %s for revision %s"
+                                % (vars(self.Class)['name'], ret, val(i), revs[i]))
+
+        def test_get_previous_children(self):
+            """Children list should be revision dependent.
+            """
+            self.s.add('parent', directory=True)
+            revs = []
+            cur_children = []
+            children = []
+            for i in range(10):
+                new_child = str(i)
+                self.s.add(new_child, 'parent')
+                self.s.set(new_child, self.val)
+                revs.append(self.s.commit('%s: %d' % (self.commit_msg, i),
+                                          self.commit_body))
+                cur_children.append(new_child)
+                children.append(list(cur_children))
+            for i in range(10):
+                ret = sorted(self.s.children('parent', revision=revs[i]))
+                self.failUnless(ret == children[i],
+                                "%s.get() returned %s not %s for revision %s"
+                                % (vars(self.Class)['name'], ret,
+                                   children[i], revs[i]))
+
+    class VersionedStorage_changed_TestCase (VersionedStorageTestCase):
+        """Test cases for VersionedStorage.changed() method."""
+
+        def test_changed(self):
+            """Changed lists should reflect past activity"""
+            self.s.add('dir', directory=True)
+            self.s.add('modified', parent='dir')
+            self.s.set('modified', 'some value to be modified')
+            self.s.add('moved', parent='dir')
+            self.s.set('moved', 'this entry will be moved')
+            self.s.add('removed', parent='dir')
+            self.s.set('removed', 'this entry will be deleted')
+            revA = self.s.commit('Initial state')
+            self.s.add('new', parent='dir')
+            self.s.set('new', 'this entry is new')
+            self.s.set('modified', 'a new value')
+            self.s.remove('moved')
+            self.s.add('moved2', parent='dir')
+            self.s.set('moved2', 'this entry will be moved')
+            self.s.remove('removed')
+            revB = self.s.commit('Final state')
+            new,mod,rem = self.s.changed(revA)
+            self.failUnless(sorted(new) == ['moved2', 'new'],
+                            'Unexpected new: %s' % new)
+            self.failUnless(mod == ['modified'],
+                            'Unexpected modified: %s' % mod)
+            self.failUnless(sorted(rem) == ['moved', 'removed'],
+                            'Unexpected removed: %s' % rem)
+
+    def make_storage_testcase_subclasses(storage_class, namespace):
+        """Make StorageTestCase subclasses for storage_class in namespace."""
+        storage_testcase_classes = [
+            c for c in (
+                ob for ob in globals().values() if isinstance(ob, type))
+            if issubclass(c, StorageTestCase) \
+                and c.Class == Storage]
+
+        for base_class in storage_testcase_classes:
+            testcase_class_name = storage_class.__name__ + base_class.__name__
+            testcase_class_bases = (base_class,)
+            testcase_class_dict = dict(base_class.__dict__)
+            testcase_class_dict['Class'] = storage_class
+            testcase_class = type(
+                testcase_class_name, testcase_class_bases, testcase_class_dict)
+            setattr(namespace, testcase_class_name, testcase_class)
+
+    def make_versioned_storage_testcase_subclasses(storage_class, namespace):
+        """Make VersionedStorageTestCase subclasses for storage_class in namespace."""
+        storage_testcase_classes = [
+            c for c in (
+                ob for ob in globals().values() if isinstance(ob, type))
+            if ((issubclass(c, StorageTestCase) \
+                     and c.Class == Storage)
+                or
+                (issubclass(c, VersionedStorageTestCase) \
+                     and c.Class == VersionedStorage))]
+
+        for base_class in storage_testcase_classes:
+            testcase_class_name = storage_class.__name__ + base_class.__name__
+            testcase_class_bases = (base_class,)
+            testcase_class_dict = dict(base_class.__dict__)
+            testcase_class_dict['Class'] = storage_class
+            testcase_class = type(
+                testcase_class_name, testcase_class_bases, testcase_class_dict)
+            setattr(namespace, testcase_class_name, testcase_class)
+
+    make_storage_testcase_subclasses(VersionedStorage, sys.modules[__name__])
+
+    unitsuite =unittest.TestLoader().loadTestsFromModule(sys.modules[__name__])
+    suite = unittest.TestSuite([unitsuite, doctest.DocTestSuite()])