Merge branch 'feature/soledad-api' into develop

Conflicts:
	src/leap/soledad/__init__.py
	src/leap/soledad/backends/couch.py
	src/leap/soledad/backends/leap_backend.py
	src/leap/soledad/backends/objectstore.py
	src/leap/soledad/tests/test_couch.py
	src/leap/soledad/tests/test_logs.py
	src/leap/soledad/tests/test_sqlcipher.py
	src/leap/soledad/util.py

1 files changed, 1221 insertions, 0 deletions

diff --git a/tests/u1db_tests/test_sync.py b/tests/u1db_tests/test_sync.py
new file mode 100644
index 00000000..551826b6
--- /dev/null
+++ b/tests/u1db_tests/test_sync.py
@@ -0,0 +1,1221 @@
+# Copyright 2011-2012 Canonical Ltd.
+#
+# This file is part of u1db.
+#
+# u1db is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3
+# as published by the Free Software Foundation.
+#
+# u1db 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 Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with u1db.  If not, see <http://www.gnu.org/licenses/>.
+
+"""The Synchronization class for U1DB."""
+
+import os
+from wsgiref import simple_server
+
+from u1db import (
+    errors,
+    sync,
+    vectorclock,
+    SyncTarget,
+    )
+
+from leap.soledad.tests import u1db_tests as tests
+
+from u1db.backends import (
+    inmemory,
+    )
+from u1db.remote import (
+    http_target,
+    )
+
+from leap.soledad.tests.u1db_tests.test_remote_sync_target import (
+    make_http_app,
+    make_oauth_http_app,
+    )
+
+simple_doc = tests.simple_doc
+nested_doc = tests.nested_doc
+
+
+def _make_local_db_and_target(test):
+    db = test.create_database('test')
+    st = db.get_sync_target()
+    return db, st
+
+
+def _make_local_db_and_http_target(test, path='test'):
+    test.startServer()
+    db = test.request_state._create_database(os.path.basename(path))
+    st = http_target.HTTPSyncTarget.connect(test.getURL(path))
+    return db, st
+
+
+def _make_local_db_and_oauth_http_target(test):
+    db, st = _make_local_db_and_http_target(test, '~/test')
+    st.set_oauth_credentials(tests.consumer1.key, tests.consumer1.secret,
+                             tests.token1.key, tests.token1.secret)
+    return db, st
+
+
+target_scenarios = [
+    ('local', {'create_db_and_target': _make_local_db_and_target}),
+    ('http', {'create_db_and_target': _make_local_db_and_http_target,
+              'make_app_with_state': make_http_app}),
+    ('oauth_http', {'create_db_and_target':
+                    _make_local_db_and_oauth_http_target,
+                    'make_app_with_state': make_oauth_http_app}),
+    ]
+
+
+class DatabaseSyncTargetTests(tests.DatabaseBaseTests,
+                              tests.TestCaseWithServer):
+
+    scenarios = (tests.multiply_scenarios(tests.DatabaseBaseTests.scenarios,
+                                          target_scenarios))
+                 #+ c_db_scenarios)
+    # whitebox true means self.db is the actual local db object
+    # against which the sync is performed
+    whitebox = True
+
+    def setUp(self):
+        super(DatabaseSyncTargetTests, self).setUp()
+        self.db, self.st = self.create_db_and_target(self)
+        self.other_changes = []
+
+    def tearDown(self):
+        # We delete them explicitly, so that connections are cleanly closed
+        del self.st
+        self.db.close()
+        del self.db
+        super(DatabaseSyncTargetTests, self).tearDown()
+
+    def receive_doc(self, doc, gen, trans_id):
+        self.other_changes.append(
+            (doc.doc_id, doc.rev, doc.get_json(), gen, trans_id))
+
+    def set_trace_hook(self, callback, shallow=False):
+        setter = (self.st._set_trace_hook if not shallow else
+                  self.st._set_trace_hook_shallow)
+        try:
+            setter(callback)
+        except NotImplementedError:
+            self.skipTest("%s does not implement _set_trace_hook"
+                          % (self.st.__class__.__name__,))
+
+    def test_get_sync_target(self):
+        self.assertIsNot(None, self.st)
+
+    def test_get_sync_info(self):
+        self.assertEqual(
+            ('test', 0, '', 0, ''), self.st.get_sync_info('other'))
+
+    def test_create_doc_updates_sync_info(self):
+        self.assertEqual(
+            ('test', 0, '', 0, ''), self.st.get_sync_info('other'))
+        self.db.create_doc_from_json(simple_doc)
+        self.assertEqual(1, self.st.get_sync_info('other')[1])
+
+    def test_record_sync_info(self):
+        self.st.record_sync_info('replica', 10, 'T-transid')
+        self.assertEqual(
+            ('test', 0, '', 10, 'T-transid'), self.st.get_sync_info('replica'))
+
+    def test_sync_exchange(self):
+        docs_by_gen = [
+            (self.make_document('doc-id', 'replica:1', simple_doc), 10,
+             'T-sid')]
+        new_gen, trans_id = self.st.sync_exchange(
+            docs_by_gen, 'replica', last_known_generation=0,
+            last_known_trans_id=None, return_doc_cb=self.receive_doc)
+        self.assertGetDoc(self.db, 'doc-id', 'replica:1', simple_doc, False)
+        self.assertTransactionLog(['doc-id'], self.db)
+        last_trans_id = self.getLastTransId(self.db)
+        self.assertEqual(([], 1, last_trans_id),
+                         (self.other_changes, new_gen, last_trans_id))
+        self.assertEqual(10, self.st.get_sync_info('replica')[3])
+
+    def test_sync_exchange_deleted(self):
+        doc = self.db.create_doc_from_json('{}')
+        edit_rev = 'replica:1|' + doc.rev
+        docs_by_gen = [
+            (self.make_document(doc.doc_id, edit_rev, None), 10, 'T-sid')]
+        new_gen, trans_id = self.st.sync_exchange(
+            docs_by_gen, 'replica', last_known_generation=0,
+            last_known_trans_id=None, return_doc_cb=self.receive_doc)
+        self.assertGetDocIncludeDeleted(
+            self.db, doc.doc_id, edit_rev, None, False)
+        self.assertTransactionLog([doc.doc_id, doc.doc_id], self.db)
+        last_trans_id = self.getLastTransId(self.db)
+        self.assertEqual(([], 2, last_trans_id),
+                         (self.other_changes, new_gen, trans_id))
+        self.assertEqual(10, self.st.get_sync_info('replica')[3])
+
+    def test_sync_exchange_push_many(self):
+        docs_by_gen = [
+            (self.make_document('doc-id', 'replica:1', simple_doc), 10, 'T-1'),
+            (self.make_document('doc-id2', 'replica:1', nested_doc), 11,
+             'T-2')]
+        new_gen, trans_id = self.st.sync_exchange(
+            docs_by_gen, 'replica', last_known_generation=0,
+            last_known_trans_id=None, return_doc_cb=self.receive_doc)
+        self.assertGetDoc(self.db, 'doc-id', 'replica:1', simple_doc, False)
+        self.assertGetDoc(self.db, 'doc-id2', 'replica:1', nested_doc, False)
+        self.assertTransactionLog(['doc-id', 'doc-id2'], self.db)
+        last_trans_id = self.getLastTransId(self.db)
+        self.assertEqual(([], 2, last_trans_id),
+                         (self.other_changes, new_gen, trans_id))
+        self.assertEqual(11, self.st.get_sync_info('replica')[3])
+
+    def test_sync_exchange_refuses_conflicts(self):
+        doc = self.db.create_doc_from_json(simple_doc)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        new_doc = '{"key": "altval"}'
+        docs_by_gen = [
+            (self.make_document(doc.doc_id, 'replica:1', new_doc), 10,
+             'T-sid')]
+        new_gen, _ = self.st.sync_exchange(
+            docs_by_gen, 'replica', last_known_generation=0,
+            last_known_trans_id=None, return_doc_cb=self.receive_doc)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        self.assertEqual(
+            (doc.doc_id, doc.rev, simple_doc, 1), self.other_changes[0][:-1])
+        self.assertEqual(1, new_gen)
+        if self.whitebox:
+            self.assertEqual(self.db._last_exchange_log['return'],
+                             {'last_gen': 1, 'docs': [(doc.doc_id, doc.rev)]})
+
+    def test_sync_exchange_ignores_convergence(self):
+        doc = self.db.create_doc_from_json(simple_doc)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        gen, txid = self.db._get_generation_info()
+        docs_by_gen = [
+            (self.make_document(doc.doc_id, doc.rev, simple_doc), 10, 'T-sid')]
+        new_gen, _ = self.st.sync_exchange(
+            docs_by_gen, 'replica', last_known_generation=gen,
+            last_known_trans_id=txid, return_doc_cb=self.receive_doc)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        self.assertEqual(([], 1), (self.other_changes, new_gen))
+
+    def test_sync_exchange_returns_new_docs(self):
+        doc = self.db.create_doc_from_json(simple_doc)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        new_gen, _ = self.st.sync_exchange(
+            [], 'other-replica', last_known_generation=0,
+            last_known_trans_id=None, return_doc_cb=self.receive_doc)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        self.assertEqual(
+            (doc.doc_id, doc.rev, simple_doc, 1), self.other_changes[0][:-1])
+        self.assertEqual(1, new_gen)
+        if self.whitebox:
+            self.assertEqual(self.db._last_exchange_log['return'],
+                             {'last_gen': 1, 'docs': [(doc.doc_id, doc.rev)]})
+
+    def test_sync_exchange_returns_deleted_docs(self):
+        doc = self.db.create_doc_from_json(simple_doc)
+        self.db.delete_doc(doc)
+        self.assertTransactionLog([doc.doc_id, doc.doc_id], self.db)
+        new_gen, _ = self.st.sync_exchange(
+            [], 'other-replica', last_known_generation=0,
+            last_known_trans_id=None, return_doc_cb=self.receive_doc)
+        self.assertTransactionLog([doc.doc_id, doc.doc_id], self.db)
+        self.assertEqual(
+            (doc.doc_id, doc.rev, None, 2), self.other_changes[0][:-1])
+        self.assertEqual(2, new_gen)
+        if self.whitebox:
+            self.assertEqual(self.db._last_exchange_log['return'],
+                             {'last_gen': 2, 'docs': [(doc.doc_id, doc.rev)]})
+
+    def test_sync_exchange_returns_many_new_docs(self):
+        doc = self.db.create_doc_from_json(simple_doc)
+        doc2 = self.db.create_doc_from_json(nested_doc)
+        self.assertTransactionLog([doc.doc_id, doc2.doc_id], self.db)
+        new_gen, _ = self.st.sync_exchange(
+            [], 'other-replica', last_known_generation=0,
+            last_known_trans_id=None, return_doc_cb=self.receive_doc)
+        self.assertTransactionLog([doc.doc_id, doc2.doc_id], self.db)
+        self.assertEqual(2, new_gen)
+        self.assertEqual(
+            [(doc.doc_id, doc.rev, simple_doc, 1),
+             (doc2.doc_id, doc2.rev, nested_doc, 2)],
+            [c[:-1] for c in self.other_changes])
+        if self.whitebox:
+            self.assertEqual(
+                self.db._last_exchange_log['return'],
+                {'last_gen': 2, 'docs':
+                 [(doc.doc_id, doc.rev), (doc2.doc_id, doc2.rev)]})
+
+    def test_sync_exchange_getting_newer_docs(self):
+        doc = self.db.create_doc_from_json(simple_doc)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        new_doc = '{"key": "altval"}'
+        docs_by_gen = [
+            (self.make_document(doc.doc_id, 'test:1|z:2', new_doc), 10,
+             'T-sid')]
+        new_gen, _ = self.st.sync_exchange(
+            docs_by_gen, 'other-replica', last_known_generation=0,
+            last_known_trans_id=None, return_doc_cb=self.receive_doc)
+        self.assertTransactionLog([doc.doc_id, doc.doc_id], self.db)
+        self.assertEqual(([], 2), (self.other_changes, new_gen))
+
+    def test_sync_exchange_with_concurrent_updates_of_synced_doc(self):
+        expected = []
+
+        def before_whatschanged_cb(state):
+            if state != 'before whats_changed':
+                return
+            cont = '{"key": "cuncurrent"}'
+            conc_rev = self.db.put_doc(
+                self.make_document(doc.doc_id, 'test:1|z:2', cont))
+            expected.append((doc.doc_id, conc_rev, cont, 3))
+
+        self.set_trace_hook(before_whatschanged_cb)
+        doc = self.db.create_doc_from_json(simple_doc)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        new_doc = '{"key": "altval"}'
+        docs_by_gen = [
+            (self.make_document(doc.doc_id, 'test:1|z:2', new_doc), 10,
+             'T-sid')]
+        new_gen, _ = self.st.sync_exchange(
+            docs_by_gen, 'other-replica', last_known_generation=0,
+            last_known_trans_id=None, return_doc_cb=self.receive_doc)
+        self.assertEqual(expected, [c[:-1] for c in self.other_changes])
+        self.assertEqual(3, new_gen)
+
+    def test_sync_exchange_with_concurrent_updates(self):
+
+        def after_whatschanged_cb(state):
+            if state != 'after whats_changed':
+                return
+            self.db.create_doc_from_json('{"new": "doc"}')
+
+        self.set_trace_hook(after_whatschanged_cb)
+        doc = self.db.create_doc_from_json(simple_doc)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        new_doc = '{"key": "altval"}'
+        docs_by_gen = [
+            (self.make_document(doc.doc_id, 'test:1|z:2', new_doc), 10,
+             'T-sid')]
+        new_gen, _ = self.st.sync_exchange(
+            docs_by_gen, 'other-replica', last_known_generation=0,
+            last_known_trans_id=None, return_doc_cb=self.receive_doc)
+        self.assertEqual(([], 2), (self.other_changes, new_gen))
+
+    def test_sync_exchange_converged_handling(self):
+        doc = self.db.create_doc_from_json(simple_doc)
+        docs_by_gen = [
+            (self.make_document('new', 'other:1', '{}'), 4, 'T-foo'),
+            (self.make_document(doc.doc_id, doc.rev, doc.get_json()), 5,
+             'T-bar')]
+        new_gen, _ = self.st.sync_exchange(
+            docs_by_gen, 'other-replica', last_known_generation=0,
+            last_known_trans_id=None, return_doc_cb=self.receive_doc)
+        self.assertEqual(([], 2), (self.other_changes, new_gen))
+
+    def test_sync_exchange_detect_incomplete_exchange(self):
+        def before_get_docs_explode(state):
+            if state != 'before get_docs':
+                return
+            raise errors.U1DBError("fail")
+        self.set_trace_hook(before_get_docs_explode)
+        # suppress traceback printing in the wsgiref server
+        self.patch(simple_server.ServerHandler,
+                   'log_exception', lambda h, exc_info: None)
+        doc = self.db.create_doc_from_json(simple_doc)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        self.assertRaises(
+            (errors.U1DBError, errors.BrokenSyncStream),
+            self.st.sync_exchange, [], 'other-replica',
+            last_known_generation=0, last_known_trans_id=None,
+            return_doc_cb=self.receive_doc)
+
+    def test_sync_exchange_doc_ids(self):
+        sync_exchange_doc_ids = getattr(self.st, 'sync_exchange_doc_ids', None)
+        if sync_exchange_doc_ids is None:
+            self.skipTest("sync_exchange_doc_ids not implemented")
+        db2 = self.create_database('test2')
+        doc = db2.create_doc_from_json(simple_doc)
+        new_gen, trans_id = sync_exchange_doc_ids(
+            db2, [(doc.doc_id, 10, 'T-sid')], 0, None,
+            return_doc_cb=self.receive_doc)
+        self.assertGetDoc(self.db, doc.doc_id, doc.rev, simple_doc, False)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        last_trans_id = self.getLastTransId(self.db)
+        self.assertEqual(([], 1, last_trans_id),
+                         (self.other_changes, new_gen, trans_id))
+        self.assertEqual(10, self.st.get_sync_info(db2._replica_uid)[3])
+
+    def test__set_trace_hook(self):
+        called = []
+
+        def cb(state):
+            called.append(state)
+
+        self.set_trace_hook(cb)
+        self.st.sync_exchange([], 'replica', 0, None, self.receive_doc)
+        self.st.record_sync_info('replica', 0, 'T-sid')
+        self.assertEqual(['before whats_changed',
+                          'after whats_changed',
+                          'before get_docs',
+                          'record_sync_info',
+                          ],
+                         called)
+
+    def test__set_trace_hook_shallow(self):
+        if (self.st._set_trace_hook_shallow == self.st._set_trace_hook
+            or self.st._set_trace_hook_shallow.im_func ==
+               SyncTarget._set_trace_hook_shallow.im_func):
+            # shallow same as full
+            expected = ['before whats_changed',
+                        'after whats_changed',
+                        'before get_docs',
+                        'record_sync_info',
+                        ]
+        else:
+            expected = ['sync_exchange', 'record_sync_info']
+
+        called = []
+
+        def cb(state):
+            called.append(state)
+
+        self.set_trace_hook(cb, shallow=True)
+        self.st.sync_exchange([], 'replica', 0, None, self.receive_doc)
+        self.st.record_sync_info('replica', 0, 'T-sid')
+        self.assertEqual(expected, called)
+
+
+def sync_via_synchronizer(test, db_source, db_target, trace_hook=None,
+                          trace_hook_shallow=None):
+    target = db_target.get_sync_target()
+    trace_hook = trace_hook or trace_hook_shallow
+    if trace_hook:
+        target._set_trace_hook(trace_hook)
+    return sync.Synchronizer(db_source, target).sync()
+
+
+sync_scenarios = []
+for name, scenario in tests.LOCAL_DATABASES_SCENARIOS:
+    scenario = dict(scenario)
+    scenario['do_sync'] = sync_via_synchronizer
+    sync_scenarios.append((name, scenario))
+    scenario = dict(scenario)
+
+
+def make_database_for_http_test(test, replica_uid):
+    if test.server is None:
+        test.startServer()
+    db = test.request_state._create_database(replica_uid)
+    try:
+        http_at = test._http_at
+    except AttributeError:
+        http_at = test._http_at = {}
+    http_at[db] = replica_uid
+    return db
+
+
+def copy_database_for_http_test(test, db):
+    # DO NOT COPY OR REUSE THIS CODE OUTSIDE TESTS: COPYING U1DB DATABASES IS
+    # THE WRONG THING TO DO, THE ONLY REASON WE DO SO HERE IS TO TEST THAT WE
+    # CORRECTLY DETECT IT HAPPENING SO THAT WE CAN RAISE ERRORS RATHER THAN
+    # CORRUPT USER DATA. USE SYNC INSTEAD, OR WE WILL SEND NINJA TO YOUR HOUSE.
+    if test.server is None:
+        test.startServer()
+    new_db = test.request_state._copy_database(db)
+    try:
+        http_at = test._http_at
+    except AttributeError:
+        http_at = test._http_at = {}
+    path = db._replica_uid
+    while path in http_at.values():
+        path += 'copy'
+    http_at[new_db] = path
+    return new_db
+
+
+def sync_via_synchronizer_and_http(test, db_source, db_target,
+                                   trace_hook=None, trace_hook_shallow=None):
+    if trace_hook:
+        test.skipTest("full trace hook unsupported over http")
+    path = test._http_at[db_target]
+    target = http_target.HTTPSyncTarget.connect(test.getURL(path))
+    if trace_hook_shallow:
+        target._set_trace_hook_shallow(trace_hook_shallow)
+    return sync.Synchronizer(db_source, target).sync()
+
+
+sync_scenarios.append(('pyhttp', {
+    'make_database_for_test': make_database_for_http_test,
+    'copy_database_for_test': copy_database_for_http_test,
+    'make_document_for_test': tests.make_document_for_test,
+    'make_app_with_state': make_http_app,
+    'do_sync': sync_via_synchronizer_and_http
+    }))
+
+
+class DatabaseSyncTests(tests.DatabaseBaseTests,
+                        tests.TestCaseWithServer):
+
+    scenarios = sync_scenarios
+    do_sync = None                 # set by scenarios
+
+    def create_database(self, replica_uid, sync_role=None):
+        if replica_uid == 'test' and sync_role is None:
+            # created up the chain by base class but unused
+            return None
+        db = self.create_database_for_role(replica_uid, sync_role)
+        if sync_role:
+            self._use_tracking[db] = (replica_uid, sync_role)
+        return db
+
+    def create_database_for_role(self, replica_uid, sync_role):
+        # hook point for reuse
+        return  super(DatabaseSyncTests, self).create_database(replica_uid)
+
+    def copy_database(self, db, sync_role=None):
+        # DO NOT COPY OR REUSE THIS CODE OUTSIDE TESTS: COPYING U1DB DATABASES
+        # IS THE WRONG THING TO DO, THE ONLY REASON WE DO SO HERE IS TO TEST
+        # THAT WE CORRECTLY DETECT IT HAPPENING SO THAT WE CAN RAISE ERRORS
+        # RATHER THAN CORRUPT USER DATA. USE SYNC INSTEAD, OR WE WILL SEND
+        # NINJA TO YOUR HOUSE.
+        db_copy = super(DatabaseSyncTests, self).copy_database(db)
+        name, orig_sync_role = self._use_tracking[db]
+        self._use_tracking[db_copy] = (name + '(copy)', sync_role
+                                       or orig_sync_role)
+        return db_copy
+
+    def sync(self, db_from, db_to, trace_hook=None,
+             trace_hook_shallow=None):
+        from_name, from_sync_role = self._use_tracking[db_from]
+        to_name, to_sync_role = self._use_tracking[db_to]
+        if from_sync_role not in ('source', 'both'):
+            raise Exception("%s marked for %s use but used as source" %
+                            (from_name, from_sync_role))
+        if to_sync_role not in ('target', 'both'):
+            raise Exception("%s marked for %s use but used as target" %
+                            (to_name, to_sync_role))
+        return self.do_sync(self, db_from, db_to, trace_hook,
+                            trace_hook_shallow)
+
+    def setUp(self):
+        self._use_tracking = {}
+        super(DatabaseSyncTests, self).setUp()
+
+    def assertLastExchangeLog(self, db, expected):
+        log = getattr(db, '_last_exchange_log', None)
+        if log is None:
+            return
+        self.assertEqual(expected, log)
+
+    def test_sync_tracks_db_generation_of_other(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        self.assertEqual(0, self.sync(self.db1, self.db2))
+        self.assertEqual(
+            (0, ''), self.db1._get_replica_gen_and_trans_id('test2'))
+        self.assertEqual(
+            (0, ''), self.db2._get_replica_gen_and_trans_id('test1'))
+        self.assertLastExchangeLog(self.db2,
+            {'receive': {'docs': [], 'last_known_gen': 0},
+             'return': {'docs': [], 'last_gen': 0}})
+
+    def test_sync_autoresolves(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        doc1 = self.db1.create_doc_from_json(simple_doc, doc_id='doc')
+        rev1 = doc1.rev
+        doc2 = self.db2.create_doc_from_json(simple_doc, doc_id='doc')
+        rev2 = doc2.rev
+        self.sync(self.db1, self.db2)
+        doc = self.db1.get_doc('doc')
+        self.assertFalse(doc.has_conflicts)
+        self.assertEqual(doc.rev, self.db2.get_doc('doc').rev)
+        v = vectorclock.VectorClockRev(doc.rev)
+        self.assertTrue(v.is_newer(vectorclock.VectorClockRev(rev1)))
+        self.assertTrue(v.is_newer(vectorclock.VectorClockRev(rev2)))
+
+    def test_sync_autoresolves_moar(self):
+        # here we test that when a database that has a conflicted document is
+        # the source of a sync, and the target database has a revision of the
+        # conflicted document that is newer than the source database's, and
+        # that target's database's document's content is the same as the
+        # source's document's conflict's, the source's document's conflict gets
+        # autoresolved, and the source's document's revision bumped.
+        #
+        # idea is as follows:
+        # A          B
+        # a1         -
+        #   `------->
+        # a1         a1
+        # v          v
+        # a2         a1b1
+        #   `------->
+        # a1b1+a2    a1b1
+        #            v
+        # a1b1+a2    a1b2 (a1b2 has same content as a2)
+        #   `------->
+        # a3b2       a1b2 (autoresolved)
+        #   `------->
+        # a3b2       a3b2
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        self.db1.create_doc_from_json(simple_doc, doc_id='doc')
+        self.sync(self.db1, self.db2)
+        for db, content in [(self.db1, '{}'), (self.db2, '{"hi": 42}')]:
+            doc = db.get_doc('doc')
+            doc.set_json(content)
+            db.put_doc(doc)
+        self.sync(self.db1, self.db2)
+        # db1 and db2 now both have a doc of {hi:42}, but db1 has a conflict
+        doc = self.db1.get_doc('doc')
+        rev1 = doc.rev
+        self.assertTrue(doc.has_conflicts)
+        # set db2 to have a doc of {} (same as db1 before the conflict)
+        doc = self.db2.get_doc('doc')
+        doc.set_json('{}')
+        self.db2.put_doc(doc)
+        rev2 = doc.rev
+        # sync it across
+        self.sync(self.db1, self.db2)
+        # tadaa!
+        doc = self.db1.get_doc('doc')
+        self.assertFalse(doc.has_conflicts)
+        vec1 = vectorclock.VectorClockRev(rev1)
+        vec2 = vectorclock.VectorClockRev(rev2)
+        vec3 = vectorclock.VectorClockRev(doc.rev)
+        self.assertTrue(vec3.is_newer(vec1))
+        self.assertTrue(vec3.is_newer(vec2))
+        # because the conflict is on the source, sync it another time
+        self.sync(self.db1, self.db2)
+        # make sure db2 now has the exact same thing
+        self.assertEqual(self.db1.get_doc('doc'), self.db2.get_doc('doc'))
+
+    def test_sync_autoresolves_moar_backwards(self):
+        # here we test that when a database that has a conflicted document is
+        # the target of a sync, and the source database has a revision of the
+        # conflicted document that is newer than the target database's, and
+        # that source's database's document's content is the same as the
+        # target's document's conflict's, the target's document's conflict gets
+        # autoresolved, and the document's revision bumped.
+        #
+        # idea is as follows:
+        # A          B
+        # a1         -
+        #   `------->
+        # a1         a1
+        # v          v
+        # a2         a1b1
+        #   `------->
+        # a1b1+a2    a1b1
+        #            v
+        # a1b1+a2    a1b2 (a1b2 has same content as a2)
+        #   <-------'
+        # a3b2       a3b2 (autoresolved and propagated)
+        self.db1 = self.create_database('test1', 'both')
+        self.db2 = self.create_database('test2', 'both')
+        self.db1.create_doc_from_json(simple_doc, doc_id='doc')
+        self.sync(self.db1, self.db2)
+        for db, content in [(self.db1, '{}'), (self.db2, '{"hi": 42}')]:
+            doc = db.get_doc('doc')
+            doc.set_json(content)
+            db.put_doc(doc)
+        self.sync(self.db1, self.db2)
+        # db1 and db2 now both have a doc of {hi:42}, but db1 has a conflict
+        doc = self.db1.get_doc('doc')
+        rev1 = doc.rev
+        self.assertTrue(doc.has_conflicts)
+        revc = self.db1.get_doc_conflicts('doc')[-1].rev
+        # set db2 to have a doc of {} (same as db1 before the conflict)
+        doc = self.db2.get_doc('doc')
+        doc.set_json('{}')
+        self.db2.put_doc(doc)
+        rev2 = doc.rev
+        # sync it across
+        self.sync(self.db2, self.db1)
+        # tadaa!
+        doc = self.db1.get_doc('doc')
+        self.assertFalse(doc.has_conflicts)
+        vec1 = vectorclock.VectorClockRev(rev1)
+        vec2 = vectorclock.VectorClockRev(rev2)
+        vec3 = vectorclock.VectorClockRev(doc.rev)
+        vecc = vectorclock.VectorClockRev(revc)
+        self.assertTrue(vec3.is_newer(vec1))
+        self.assertTrue(vec3.is_newer(vec2))
+        self.assertTrue(vec3.is_newer(vecc))
+        # make sure db2 now has the exact same thing
+        self.assertEqual(self.db1.get_doc('doc'), self.db2.get_doc('doc'))
+
+    def test_sync_autoresolves_moar_backwards_three(self):
+        # same as autoresolves_moar_backwards, but with three databases (note
+        # all the syncs go in the same direction -- this is a more natural
+        # scenario):
+        #
+        # A          B          C
+        # a1         -          -
+        #   `------->
+        # a1         a1         -
+        #              `------->
+        # a1         a1         a1
+        # v          v
+        # a2         a1b1       a1
+        #  `------------------->
+        # a2         a1b1       a2
+        #              `------->
+        #            a2+a1b1    a2
+        #                       v
+        # a2         a2+a1b1    a2c1 (same as a1b1)
+        #  `------------------->
+        # a2c1       a2+a1b1    a2c1
+        #   `------->
+        # a2b2c1     a2b2c1     a2c1
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'both')
+        self.db3 = self.create_database('test3', 'target')
+        self.db1.create_doc_from_json(simple_doc, doc_id='doc')
+        self.sync(self.db1, self.db2)
+        self.sync(self.db2, self.db3)
+        for db, content in [(self.db2, '{"hi": 42}'),
+                            (self.db1, '{}'),
+                            ]:
+            doc = db.get_doc('doc')
+            doc.set_json(content)
+            db.put_doc(doc)
+        self.sync(self.db1, self.db3)
+        self.sync(self.db2, self.db3)
+        # db2 and db3 now both have a doc of {}, but db2 has a
+        # conflict
+        doc = self.db2.get_doc('doc')
+        self.assertTrue(doc.has_conflicts)
+        revc = self.db2.get_doc_conflicts('doc')[-1].rev
+        self.assertEqual('{}', doc.get_json())
+        self.assertEqual(self.db3.get_doc('doc').get_json(), doc.get_json())
+        self.assertEqual(self.db3.get_doc('doc').rev, doc.rev)
+        # set db3 to have a doc of {hi:42} (same as db2 before the conflict)
+        doc = self.db3.get_doc('doc')
+        doc.set_json('{"hi": 42}')
+        self.db3.put_doc(doc)
+        rev3 = doc.rev
+        # sync it across to db1
+        self.sync(self.db1, self.db3)
+        # db1 now has hi:42, with a rev that is newer than db2's doc
+        doc = self.db1.get_doc('doc')
+        rev1 = doc.rev
+        self.assertFalse(doc.has_conflicts)
+        self.assertEqual('{"hi": 42}', doc.get_json())
+        VCR = vectorclock.VectorClockRev
+        self.assertTrue(VCR(rev1).is_newer(VCR(self.db2.get_doc('doc').rev)))
+        # so sync it to db2
+        self.sync(self.db1, self.db2)
+        # tadaa!
+        doc = self.db2.get_doc('doc')
+        self.assertFalse(doc.has_conflicts)
+        # db2's revision of the document is strictly newer than db1's before
+        # the sync, and db3's before that sync way back when
+        self.assertTrue(VCR(doc.rev).is_newer(VCR(rev1)))
+        self.assertTrue(VCR(doc.rev).is_newer(VCR(rev3)))
+        self.assertTrue(VCR(doc.rev).is_newer(VCR(revc)))
+        # make sure both dbs now have the exact same thing
+        self.assertEqual(self.db1.get_doc('doc'), self.db2.get_doc('doc'))
+
+    def test_sync_puts_changes(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        doc = self.db1.create_doc_from_json(simple_doc)
+        self.assertEqual(1, self.sync(self.db1, self.db2))
+        self.assertGetDoc(self.db2, doc.doc_id, doc.rev, simple_doc, False)
+        self.assertEqual(1, self.db1._get_replica_gen_and_trans_id('test2')[0])
+        self.assertEqual(1, self.db2._get_replica_gen_and_trans_id('test1')[0])
+        self.assertLastExchangeLog(self.db2,
+            {'receive': {'docs': [(doc.doc_id, doc.rev)],
+                         'source_uid': 'test1',
+                         'source_gen': 1, 'last_known_gen': 0},
+             'return': {'docs': [], 'last_gen': 1}})
+
+    def test_sync_pulls_changes(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        doc = self.db2.create_doc_from_json(simple_doc)
+        self.db1.create_index('test-idx', 'key')
+        self.assertEqual(0, self.sync(self.db1, self.db2))
+        self.assertGetDoc(self.db1, doc.doc_id, doc.rev, simple_doc, False)
+        self.assertEqual(1, self.db1._get_replica_gen_and_trans_id('test2')[0])
+        self.assertEqual(1, self.db2._get_replica_gen_and_trans_id('test1')[0])
+        self.assertLastExchangeLog(self.db2,
+            {'receive': {'docs': [], 'last_known_gen': 0},
+             'return': {'docs': [(doc.doc_id, doc.rev)],
+                        'last_gen': 1}})
+        self.assertEqual([doc], self.db1.get_from_index('test-idx', 'value'))
+
+    def test_sync_pulling_doesnt_update_other_if_changed(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        doc = self.db2.create_doc_from_json(simple_doc)
+        # After the local side has sent its list of docs, before we start
+        # receiving the "targets" response, we update the local database with a
+        # new record.
+        # When we finish synchronizing, we can notice that something locally
+        # was updated, and we cannot tell c2 our new updated generation
+
+        def before_get_docs(state):
+            if state != 'before get_docs':
+                return
+            self.db1.create_doc_from_json(simple_doc)
+
+        self.assertEqual(0, self.sync(self.db1, self.db2,
+                                      trace_hook=before_get_docs))
+        self.assertLastExchangeLog(self.db2,
+            {'receive': {'docs': [], 'last_known_gen': 0},
+             'return': {'docs': [(doc.doc_id, doc.rev)],
+                        'last_gen': 1}})
+        self.assertEqual(1, self.db1._get_replica_gen_and_trans_id('test2')[0])
+        # c2 should not have gotten a '_record_sync_info' call, because the
+        # local database had been updated more than just by the messages
+        # returned from c2.
+        self.assertEqual(
+            (0, ''), self.db2._get_replica_gen_and_trans_id('test1'))
+
+    def test_sync_doesnt_update_other_if_nothing_pulled(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        self.db1.create_doc_from_json(simple_doc)
+
+        def no_record_sync_info(state):
+            if state != 'record_sync_info':
+                return
+            self.fail('SyncTarget.record_sync_info was called')
+        self.assertEqual(1, self.sync(self.db1, self.db2,
+                                      trace_hook_shallow=no_record_sync_info))
+        self.assertEqual(
+            1,
+            self.db2._get_replica_gen_and_trans_id(self.db1._replica_uid)[0])
+
+    def test_sync_ignores_convergence(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'both')
+        doc = self.db1.create_doc_from_json(simple_doc)
+        self.db3 = self.create_database('test3', 'target')
+        self.assertEqual(1, self.sync(self.db1, self.db3))
+        self.assertEqual(0, self.sync(self.db2, self.db3))
+        self.assertEqual(1, self.sync(self.db1, self.db2))
+        self.assertLastExchangeLog(self.db2,
+            {'receive': {'docs': [(doc.doc_id, doc.rev)],
+                         'source_uid': 'test1',
+                         'source_gen': 1, 'last_known_gen': 0},
+             'return': {'docs': [], 'last_gen': 1}})
+
+    def test_sync_ignores_superseded(self):
+        self.db1 = self.create_database('test1', 'both')
+        self.db2 = self.create_database('test2', 'both')
+        doc = self.db1.create_doc_from_json(simple_doc)
+        doc_rev1 = doc.rev
+        self.db3 = self.create_database('test3', 'target')
+        self.sync(self.db1, self.db3)
+        self.sync(self.db2, self.db3)
+        new_content = '{"key": "altval"}'
+        doc.set_json(new_content)
+        self.db1.put_doc(doc)
+        doc_rev2 = doc.rev
+        self.sync(self.db2, self.db1)
+        self.assertLastExchangeLog(self.db1,
+            {'receive': {'docs': [(doc.doc_id, doc_rev1)],
+                         'source_uid': 'test2',
+                         'source_gen': 1, 'last_known_gen': 0},
+             'return': {'docs': [(doc.doc_id, doc_rev2)],
+                        'last_gen': 2}})
+        self.assertGetDoc(self.db1, doc.doc_id, doc_rev2, new_content, False)
+
+    def test_sync_sees_remote_conflicted(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        doc1 = self.db1.create_doc_from_json(simple_doc)
+        doc_id = doc1.doc_id
+        doc1_rev = doc1.rev
+        self.db1.create_index('test-idx', 'key')
+        new_doc = '{"key": "altval"}'
+        doc2 = self.db2.create_doc_from_json(new_doc, doc_id=doc_id)
+        doc2_rev = doc2.rev
+        self.assertTransactionLog([doc1.doc_id], self.db1)
+        self.sync(self.db1, self.db2)
+        self.assertLastExchangeLog(self.db2,
+            {'receive': {'docs': [(doc_id, doc1_rev)],
+                         'source_uid': 'test1',
+                         'source_gen': 1, 'last_known_gen': 0},
+             'return': {'docs': [(doc_id, doc2_rev)],
+                        'last_gen': 1}})
+        self.assertTransactionLog([doc_id, doc_id], self.db1)
+        self.assertGetDoc(self.db1, doc_id, doc2_rev, new_doc, True)
+        self.assertGetDoc(self.db2, doc_id, doc2_rev, new_doc, False)
+        from_idx = self.db1.get_from_index('test-idx', 'altval')[0]
+        self.assertEqual(doc2.doc_id, from_idx.doc_id)
+        self.assertEqual(doc2.rev, from_idx.rev)
+        self.assertTrue(from_idx.has_conflicts)
+        self.assertEqual([], self.db1.get_from_index('test-idx', 'value'))
+
+    def test_sync_sees_remote_delete_conflicted(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        doc1 = self.db1.create_doc_from_json(simple_doc)
+        doc_id = doc1.doc_id
+        self.db1.create_index('test-idx', 'key')
+        self.sync(self.db1, self.db2)
+        doc2 = self.make_document(doc1.doc_id, doc1.rev, doc1.get_json())
+        new_doc = '{"key": "altval"}'
+        doc1.set_json(new_doc)
+        self.db1.put_doc(doc1)
+        self.db2.delete_doc(doc2)
+        self.assertTransactionLog([doc_id, doc_id], self.db1)
+        self.sync(self.db1, self.db2)
+        self.assertLastExchangeLog(self.db2,
+            {'receive': {'docs': [(doc_id, doc1.rev)],
+                         'source_uid': 'test1',
+                         'source_gen': 2, 'last_known_gen': 1},
+             'return': {'docs': [(doc_id, doc2.rev)],
+                        'last_gen': 2}})
+        self.assertTransactionLog([doc_id, doc_id, doc_id], self.db1)
+        self.assertGetDocIncludeDeleted(self.db1, doc_id, doc2.rev, None, True)
+        self.assertGetDocIncludeDeleted(
+            self.db2, doc_id, doc2.rev, None, False)
+        self.assertEqual([], self.db1.get_from_index('test-idx', 'value'))
+
+    def test_sync_local_race_conflicted(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        doc = self.db1.create_doc_from_json(simple_doc)
+        doc_id = doc.doc_id
+        doc1_rev = doc.rev
+        self.db1.create_index('test-idx', 'key')
+        self.sync(self.db1, self.db2)
+        content1 = '{"key": "localval"}'
+        content2 = '{"key": "altval"}'
+        doc.set_json(content2)
+        self.db2.put_doc(doc)
+        doc2_rev2 = doc.rev
+        triggered = []
+
+        def after_whatschanged(state):
+            if state != 'after whats_changed':
+                return
+            triggered.append(True)
+            doc = self.make_document(doc_id, doc1_rev, content1)
+            self.db1.put_doc(doc)
+
+        self.sync(self.db1, self.db2, trace_hook=after_whatschanged)
+        self.assertEqual([True], triggered)
+        self.assertGetDoc(self.db1, doc_id, doc2_rev2, content2, True)
+        from_idx = self.db1.get_from_index('test-idx', 'altval')[0]
+        self.assertEqual(doc.doc_id, from_idx.doc_id)
+        self.assertEqual(doc.rev, from_idx.rev)
+        self.assertTrue(from_idx.has_conflicts)
+        self.assertEqual([], self.db1.get_from_index('test-idx', 'value'))
+        self.assertEqual([], self.db1.get_from_index('test-idx', 'localval'))
+
+    def test_sync_propagates_deletes(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'both')
+        doc1 = self.db1.create_doc_from_json(simple_doc)
+        doc_id = doc1.doc_id
+        self.db1.create_index('test-idx', 'key')
+        self.sync(self.db1, self.db2)
+        self.db2.create_index('test-idx', 'key')
+        self.db3 = self.create_database('test3', 'target')
+        self.sync(self.db1, self.db3)
+        self.db1.delete_doc(doc1)
+        deleted_rev = doc1.rev
+        self.sync(self.db1, self.db2)
+        self.assertLastExchangeLog(self.db2,
+            {'receive': {'docs': [(doc_id, deleted_rev)],
+                         'source_uid': 'test1',
+                         'source_gen': 2, 'last_known_gen': 1},
+             'return': {'docs': [], 'last_gen': 2}})
+        self.assertGetDocIncludeDeleted(
+            self.db1, doc_id, deleted_rev, None, False)
+        self.assertGetDocIncludeDeleted(
+            self.db2, doc_id, deleted_rev, None, False)
+        self.assertEqual([], self.db1.get_from_index('test-idx', 'value'))
+        self.assertEqual([], self.db2.get_from_index('test-idx', 'value'))
+        self.sync(self.db2, self.db3)
+        self.assertLastExchangeLog(self.db3,
+            {'receive': {'docs': [(doc_id, deleted_rev)],
+                         'source_uid': 'test2',
+                         'source_gen': 2, 'last_known_gen': 0},
+             'return': {'docs': [], 'last_gen': 2}})
+        self.assertGetDocIncludeDeleted(
+            self.db3, doc_id, deleted_rev, None, False)
+
+    def test_sync_propagates_resolution(self):
+        self.db1 = self.create_database('test1', 'both')
+        self.db2 = self.create_database('test2', 'both')
+        doc1 = self.db1.create_doc_from_json('{"a": 1}', doc_id='the-doc')
+        db3 = self.create_database('test3', 'both')
+        self.sync(self.db2, self.db1)
+        self.assertEqual(
+            self.db1._get_generation_info(),
+            self.db2._get_replica_gen_and_trans_id(self.db1._replica_uid))
+        self.assertEqual(
+            self.db2._get_generation_info(),
+            self.db1._get_replica_gen_and_trans_id(self.db2._replica_uid))
+        self.sync(db3, self.db1)
+        # update on 2
+        doc2 = self.make_document('the-doc', doc1.rev, '{"a": 2}')
+        self.db2.put_doc(doc2)
+        self.sync(self.db2, db3)
+        self.assertEqual(db3.get_doc('the-doc').rev, doc2.rev)
+        # update on 1
+        doc1.set_json('{"a": 3}')
+        self.db1.put_doc(doc1)
+        # conflicts
+        self.sync(self.db2, self.db1)
+        self.sync(db3, self.db1)
+        self.assertTrue(self.db2.get_doc('the-doc').has_conflicts)
+        self.assertTrue(db3.get_doc('the-doc').has_conflicts)
+        # resolve
+        conflicts = self.db2.get_doc_conflicts('the-doc')
+        doc4 = self.make_document('the-doc', None, '{"a": 4}')
+        revs = [doc.rev for doc in conflicts]
+        self.db2.resolve_doc(doc4, revs)
+        doc2 = self.db2.get_doc('the-doc')
+        self.assertEqual(doc4.get_json(), doc2.get_json())
+        self.assertFalse(doc2.has_conflicts)
+        self.sync(self.db2, db3)
+        doc3 = db3.get_doc('the-doc')
+        self.assertEqual(doc4.get_json(), doc3.get_json())
+        self.assertFalse(doc3.has_conflicts)
+
+    def test_sync_supersedes_conflicts(self):
+        self.db1 = self.create_database('test1', 'both')
+        self.db2 = self.create_database('test2', 'target')
+        db3 = self.create_database('test3', 'both')
+        doc1 = self.db1.create_doc_from_json('{"a": 1}', doc_id='the-doc')
+        self.db2.create_doc_from_json('{"b": 1}', doc_id='the-doc')
+        db3.create_doc_from_json('{"c": 1}', doc_id='the-doc')
+        self.sync(db3, self.db1)
+        self.assertEqual(
+            self.db1._get_generation_info(),
+            db3._get_replica_gen_and_trans_id(self.db1._replica_uid))
+        self.assertEqual(
+            db3._get_generation_info(),
+            self.db1._get_replica_gen_and_trans_id(db3._replica_uid))
+        self.sync(db3, self.db2)
+        self.assertEqual(
+            self.db2._get_generation_info(),
+            db3._get_replica_gen_and_trans_id(self.db2._replica_uid))
+        self.assertEqual(
+            db3._get_generation_info(),
+            self.db2._get_replica_gen_and_trans_id(db3._replica_uid))
+        self.assertEqual(3, len(db3.get_doc_conflicts('the-doc')))
+        doc1.set_json('{"a": 2}')
+        self.db1.put_doc(doc1)
+        self.sync(db3, self.db1)
+        # original doc1 should have been removed from conflicts
+        self.assertEqual(3, len(db3.get_doc_conflicts('the-doc')))
+
+    def test_sync_stops_after_get_sync_info(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        self.db1.create_doc_from_json(tests.simple_doc)
+        self.sync(self.db1, self.db2)
+
+        def put_hook(state):
+            self.fail("Tracehook triggered for %s" % (state,))
+
+        self.sync(self.db1, self.db2, trace_hook_shallow=put_hook)
+
+    def test_sync_detects_rollback_in_source(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        self.db1.create_doc_from_json(tests.simple_doc, doc_id='doc1')
+        self.sync(self.db1, self.db2)
+        db1_copy = self.copy_database(self.db1)
+        self.db1.create_doc_from_json(tests.simple_doc, doc_id='doc2')
+        self.sync(self.db1, self.db2)
+        self.assertRaises(
+            errors.InvalidGeneration, self.sync, db1_copy, self.db2)
+
+    def test_sync_detects_rollback_in_target(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        self.db1.create_doc_from_json(tests.simple_doc, doc_id="divergent")
+        self.sync(self.db1, self.db2)
+        db2_copy = self.copy_database(self.db2)
+        self.db2.create_doc_from_json(tests.simple_doc, doc_id='doc2')
+        self.sync(self.db1, self.db2)
+        self.assertRaises(
+            errors.InvalidGeneration, self.sync, self.db1, db2_copy)
+
+    def test_sync_detects_diverged_source(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        db3 = self.copy_database(self.db1)
+        self.db1.create_doc_from_json(tests.simple_doc, doc_id="divergent")
+        db3.create_doc_from_json(tests.simple_doc, doc_id="divergent")
+        self.sync(self.db1, self.db2)
+        self.assertRaises(
+            errors.InvalidTransactionId, self.sync, db3, self.db2)
+
+    def test_sync_detects_diverged_target(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        db3 = self.copy_database(self.db2)
+        db3.create_doc_from_json(tests.nested_doc, doc_id="divergent")
+        self.db1.create_doc_from_json(tests.simple_doc, doc_id="divergent")
+        self.sync(self.db1, self.db2)
+        self.assertRaises(
+            errors.InvalidTransactionId, self.sync, self.db1, db3)
+
+    def test_sync_detects_rollback_and_divergence_in_source(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        self.db1.create_doc_from_json(tests.simple_doc, doc_id='doc1')
+        self.sync(self.db1, self.db2)
+        db1_copy = self.copy_database(self.db1)
+        self.db1.create_doc_from_json(tests.simple_doc, doc_id='doc2')
+        self.db1.create_doc_from_json(tests.simple_doc, doc_id='doc3')
+        self.sync(self.db1, self.db2)
+        db1_copy.create_doc_from_json(tests.simple_doc, doc_id='doc2')
+        db1_copy.create_doc_from_json(tests.simple_doc, doc_id='doc3')
+        self.assertRaises(
+            errors.InvalidTransactionId, self.sync, db1_copy, self.db2)
+
+    def test_sync_detects_rollback_and_divergence_in_target(self):
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        self.db1.create_doc_from_json(tests.simple_doc, doc_id="divergent")
+        self.sync(self.db1, self.db2)
+        db2_copy = self.copy_database(self.db2)
+        self.db2.create_doc_from_json(tests.simple_doc, doc_id='doc2')
+        self.db2.create_doc_from_json(tests.simple_doc, doc_id='doc3')
+        self.sync(self.db1, self.db2)
+        db2_copy.create_doc_from_json(tests.simple_doc, doc_id='doc2')
+        db2_copy.create_doc_from_json(tests.simple_doc, doc_id='doc3')
+        self.assertRaises(
+            errors.InvalidTransactionId, self.sync, self.db1, db2_copy)
+
+
+class TestDbSync(tests.TestCaseWithServer):
+    """Test db.sync remote sync shortcut"""
+
+    scenarios = [
+        ('py-http', {
+            'make_app_with_state': make_http_app,
+            'make_database_for_test': tests.make_memory_database_for_test,
+            }),
+        ('py-oauth-http', {
+            'make_app_with_state': make_oauth_http_app,
+            'make_database_for_test': tests.make_memory_database_for_test,
+            'oauth': True
+            }),
+        ]
+
+    oauth = False
+
+    def do_sync(self, target_name):
+        if self.oauth:
+            path = '~/' + target_name
+            extra = dict(creds={'oauth': {
+                'consumer_key': tests.consumer1.key,
+                'consumer_secret': tests.consumer1.secret,
+                'token_key': tests.token1.key,
+                'token_secret': tests.token1.secret
+                }})
+        else:
+            path = target_name
+            extra = {}
+        target_url = self.getURL(path)
+        return self.db.sync(target_url, **extra)
+
+    def setUp(self):
+        super(TestDbSync, self).setUp()
+        self.startServer()
+        self.db = self.make_database_for_test(self, 'test1')
+        self.db2 = self.request_state._create_database('test2.db')
+
+    def test_db_sync(self):
+        doc1 = self.db.create_doc_from_json(tests.simple_doc)
+        doc2 = self.db2.create_doc_from_json(tests.nested_doc)
+        local_gen_before_sync = self.do_sync('test2.db')
+        gen, _, changes = self.db.whats_changed(local_gen_before_sync)
+        self.assertEqual(1, len(changes))
+        self.assertEqual(doc2.doc_id, changes[0][0])
+        self.assertEqual(1, gen - local_gen_before_sync)
+        self.assertGetDoc(self.db2, doc1.doc_id, doc1.rev, tests.simple_doc,
+                          False)
+        self.assertGetDoc(self.db, doc2.doc_id, doc2.rev, tests.nested_doc,
+                          False)
+
+    def test_db_sync_autocreate(self):
+        doc1 = self.db.create_doc_from_json(tests.simple_doc)
+        local_gen_before_sync = self.do_sync('test3.db')
+        gen, _, changes = self.db.whats_changed(local_gen_before_sync)
+        self.assertEqual(0, gen - local_gen_before_sync)
+        db3 = self.request_state.open_database('test3.db')
+        gen, _, changes = db3.whats_changed()
+        self.assertEqual(1, len(changes))
+        self.assertEqual(doc1.doc_id, changes[0][0])
+        self.assertGetDoc(db3, doc1.doc_id, doc1.rev, tests.simple_doc,
+                          False)
+        t_gen, _ = self.db._get_replica_gen_and_trans_id('test3.db')
+        s_gen, _ = db3._get_replica_gen_and_trans_id('test1')
+        self.assertEqual(1, t_gen)
+        self.assertEqual(1, s_gen)
+
+
+class TestRemoteSyncIntegration(tests.TestCaseWithServer):
+    """Integration tests for the most common sync scenario local -> remote"""
+
+    make_app_with_state = staticmethod(make_http_app)
+
+    def setUp(self):
+        super(TestRemoteSyncIntegration, self).setUp()
+        self.startServer()
+        self.db1 = inmemory.InMemoryDatabase('test1')
+        self.db2 = self.request_state._create_database('test2')
+
+    def test_sync_tracks_generations_incrementally(self):
+        doc11 = self.db1.create_doc_from_json('{"a": 1}')
+        doc12 = self.db1.create_doc_from_json('{"a": 2}')
+        doc21 = self.db2.create_doc_from_json('{"b": 1}')
+        doc22 = self.db2.create_doc_from_json('{"b": 2}')
+        #sanity
+        self.assertEqual(2, len(self.db1._get_transaction_log()))
+        self.assertEqual(2, len(self.db2._get_transaction_log()))
+        progress1 = []
+        progress2 = []
+        _do_set_replica_gen_and_trans_id = \
+            self.db1._do_set_replica_gen_and_trans_id
+
+        def set_sync_generation_witness1(other_uid, other_gen, trans_id):
+            progress1.append((other_uid, other_gen,
+                [d for d, t in self.db1._get_transaction_log()[2:]]))
+            _do_set_replica_gen_and_trans_id(other_uid, other_gen, trans_id)
+        self.patch(self.db1, '_do_set_replica_gen_and_trans_id',
+                   set_sync_generation_witness1)
+        _do_set_replica_gen_and_trans_id2 = \
+            self.db2._do_set_replica_gen_and_trans_id
+
+        def set_sync_generation_witness2(other_uid, other_gen, trans_id):
+            progress2.append((other_uid, other_gen,
+                [d for d, t in self.db2._get_transaction_log()[2:]]))
+            _do_set_replica_gen_and_trans_id2(other_uid, other_gen, trans_id)
+        self.patch(self.db2, '_do_set_replica_gen_and_trans_id',
+                   set_sync_generation_witness2)
+
+        db2_url = self.getURL('test2')
+        self.db1.sync(db2_url)
+
+        self.assertEqual([('test2', 1, [doc21.doc_id]),
+                          ('test2', 2, [doc21.doc_id, doc22.doc_id]),
+                          ('test2', 4, [doc21.doc_id, doc22.doc_id])],
+                         progress1)
+        self.assertEqual([('test1', 1, [doc11.doc_id]),
+                          ('test1', 2, [doc11.doc_id, doc12.doc_id]),
+                          ('test1', 4, [doc11.doc_id, doc12.doc_id])],
+                         progress2)
+
+
+load_tests = tests.load_with_scenarios