path: root/testing/tests/couch/test_sync.py

from leap.soledad.common.l2db import vectorclock
from leap.soledad.common.l2db import errors as u1db_errors

from testscenarios import TestWithScenarios

from test_soledad import u1db_tests as tests
from test_soledad.util import CouchDBTestCase
from test_soledad.util import sync_via_synchronizer
from test_soledad.u1db_tests import DatabaseBaseTests

from .common import simple_doc
from .common import COUCH_SCENARIOS


sync_scenarios = []
for name, scenario in COUCH_SCENARIOS:
    scenario = dict(scenario)
    scenario['do_sync'] = sync_via_synchronizer
    sync_scenarios.append((name, scenario))
    scenario = dict(scenario)


# -----------------------------------------------------------------------------
# The following tests come from `u1db.tests.test_sync`.
# -----------------------------------------------------------------------------

class CouchBackendSyncTests(
        TestWithScenarios,
        DatabaseBaseTests,
        CouchDBTestCase):

    scenarios = sync_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 DatabaseBaseTests.create_database(self, 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 = self.copy_database_for_test(self, 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.db = None
        self.db1 = None
        self.db2 = None
        self.db3 = None
        self.db1_copy = None
        self.db2_copy = None
        self._use_tracking = {}
        DatabaseBaseTests.setUp(self)

    def tearDown(self):
        for db in [
            self.db, self.db1, self.db2,
            self.db3, self.db1_copy, self.db2_copy
        ]:
            if db is not None:
                self.delete_db(db._dbname)
                db.close()
        DatabaseBaseTests.tearDown(self)

    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.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.assertGetDoc(self.db2, doc.doc_id, doc.rev, simple_doc, False)

    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
        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)

    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.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)

    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.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)

    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.sync(self.db1, self.db2)
        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.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_deletes_2(self):
        self.db1 = self.create_database('test1', 'source')
        self.db2 = self.create_database('test2', 'target')
        self.db1.create_doc_from_json('{"a": "1"}', doc_id='the-doc')
        self.sync(self.db1, self.db2)
        doc1_2 = self.db2.get_doc('the-doc')
        self.db2.delete_doc(doc1_2)
        self.sync(self.db1, self.db2)
        self.assertGetDocIncludeDeleted(
            self.db1, 'the-doc', doc1_2.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')
        self.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(self.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, self.db3)
        self.assertEqual(self.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(self.db3, self.db1)
        self.assertTrue(self.db2.get_doc('the-doc').has_conflicts)
        self.assertTrue(self.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, self.db3)
        doc3 = self.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')
        self.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')
        self.db3.create_doc_from_json('{"c": 1}', doc_id='the-doc')
        self.sync(self.db3, self.db1)
        self.assertEqual(
            self.db1._get_generation_info(),
            self.db3._get_replica_gen_and_trans_id(self.db1._replica_uid))
        self.assertEqual(
            self.db3._get_generation_info(),
            self.db1._get_replica_gen_and_trans_id(self.db3._replica_uid))
        self.sync(self.db3, self.db2)
        self.assertEqual(
            self.db2._get_generation_info(),
            self.db3._get_replica_gen_and_trans_id(self.db2._replica_uid))
        self.assertEqual(
            self.db3._get_generation_info(),
            self.db2._get_replica_gen_and_trans_id(self.db3._replica_uid))
        self.assertEqual(3, len(self.db3.get_doc_conflicts('the-doc')))
        doc1.set_json('{"a": 2}')
        self.db1.put_doc(doc1)
        self.sync(self.db3, self.db1)
        # original doc1 should have been removed from conflicts
        self.assertEqual(3, len(self.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_identical_replica_uid(self):
        self.db1 = self.create_database('test1', 'source')
        self.db2 = self.create_database('test1', 'target')
        self.db1.create_doc_from_json(tests.simple_doc, doc_id='doc1')
        self.assertRaises(
            u1db_errors.InvalidReplicaUID, self.sync, self.db1, self.db2)

    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)
        self.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(
            u1db_errors.InvalidGeneration, self.sync, self.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)
        self.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(
            u1db_errors.InvalidGeneration, self.sync, self.db1, self.db2_copy)

    def test_sync_detects_diverged_source(self):
        self.db1 = self.create_database('test1', 'source')
        self.db2 = self.create_database('test2', 'target')
        self.db3 = self.copy_database(self.db1)
        self.db1.create_doc_from_json(tests.simple_doc, doc_id="divergent")
        self.db3.create_doc_from_json(tests.simple_doc, doc_id="divergent")
        self.sync(self.db1, self.db2)
        self.assertRaises(
            u1db_errors.InvalidTransactionId, self.sync, self.db3, self.db2)

    def test_sync_detects_diverged_target(self):
        self.db1 = self.create_database('test1', 'source')
        self.db2 = self.create_database('test2', 'target')
        self.db3 = self.copy_database(self.db2)
        self.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(
            u1db_errors.InvalidTransactionId, self.sync, self.db1, self.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)
        self.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)
        self.db1_copy.create_doc_from_json(tests.simple_doc, doc_id='doc2')
        self.db1_copy.create_doc_from_json(tests.simple_doc, doc_id='doc3')
        self.assertRaises(
            u1db_errors.InvalidTransactionId, self.sync,
            self.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)
        self.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)
        self.db2_copy.create_doc_from_json(tests.simple_doc, doc_id='doc2')
        self.db2_copy.create_doc_from_json(tests.simple_doc, doc_id='doc3')
        self.assertRaises(
            u1db_errors.InvalidTransactionId, self.sync,
            self.db1, self.db2_copy)

    def test_optional_sync_preserve_json(self):
        self.db1 = self.create_database('test1', 'source')
        self.db2 = self.create_database('test2', 'target')
        cont1 = '{"a": 2}'
        cont2 = '{"b": 3}'
        self.db1.create_doc_from_json(cont1, doc_id="1")
        self.db2.create_doc_from_json(cont2, doc_id="2")
        self.sync(self.db1, self.db2)
        self.assertEqual(cont1, self.db2.get_doc("1").get_json())
        self.assertEqual(cont2, self.db1.get_doc("2").get_json())