[refactor] move tests to root of repository

Tests entrypoint was in a testing/ subfolder in the root of the
repository. This was made mainly because we had some common files for
tests and we didn't want to ship them (files in testing/test_soledad,
which is itself a python package. This sometimes causes errors when
loading tests (it seems setuptools is confused with having one python
package in a subdirectory of another).

This commit moves the tests entrypoint to the root of the repository.

Closes: #8952

6 files changed, 2054 insertions, 0 deletions

diff --git a/tests/sync/__init__.py b/tests/sync/__init__.py
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/tests/sync/__init__.py
diff --git a/tests/sync/test_soledad b/tests/sync/test_soledad
new file mode 120000
index 00000000..c1a35d32
--- /dev/null
+++ b/tests/sync/test_soledad
@@ -0,0 +1 @@
+../test_soledad
\ No newline at end of file
diff --git a/tests/sync/test_sqlcipher_sync.py b/tests/sync/test_sqlcipher_sync.py
new file mode 100644
index 00000000..26f63a40
--- /dev/null
+++ b/tests/sync/test_sqlcipher_sync.py
@@ -0,0 +1,719 @@
+# -*- coding: utf-8 -*-
+# test_sqlcipher.py
+# Copyright (C) 2013-2016 LEAP
+#
+# 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 3 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, see <http://www.gnu.org/licenses/>.
+"""
+Test sqlcipher backend sync.
+"""
+import os
+
+from uuid import uuid4
+
+from testscenarios import TestWithScenarios
+
+from leap.soledad.common.l2db import sync
+from leap.soledad.common.l2db import vectorclock
+from leap.soledad.common.l2db import errors
+
+from leap.soledad.client.http_target import SoledadHTTPSyncTarget
+
+from test_soledad import u1db_tests as tests
+from test_soledad.util import SQLCIPHER_SCENARIOS
+from test_soledad.util import make_soledad_app
+from test_soledad.util import soledad_sync_target
+from test_soledad.util import BaseSoledadTest
+
+
+# -----------------------------------------------------------------------------
+# The following tests come from `u1db.tests.test_sync`.
+# -----------------------------------------------------------------------------
+
+def sync_via_synchronizer_and_soledad(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 = SoledadHTTPSyncTarget.connect(
+        test.getURL(path), test._soledad._crypto)
+    target.set_token_credentials('user-uuid', 'auth-token')
+    if trace_hook_shallow:
+        target._set_trace_hook_shallow(trace_hook_shallow)
+    return sync.Synchronizer(db_source, target).sync()
+
+
+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 SQLCIPHER_SCENARIOS:
+    scenario['do_sync'] = sync_via_synchronizer
+    sync_scenarios.append((name, scenario))
+
+
+class SQLCipherDatabaseSyncTests(
+        TestWithScenarios,
+        tests.DatabaseBaseTests,
+        BaseSoledadTest):
+
+    """
+    Test for succesfull sync between SQLCipher and LeapBackend.
+
+    Some of the tests in this class had to be adapted because the remote
+    backend always receive encrypted content, and so it can not rely on
+    document's content comparison to try to autoresolve conflicts.
+    """
+
+    scenarios = sync_scenarios
+
+    def setUp(self):
+        self._use_tracking = {}
+        super(tests.DatabaseBaseTests, self).setUp()
+
+    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)
+        self.addCleanup(db.close)
+        return db
+
+    def create_database_for_role(self, replica_uid, sync_role):
+        # hook point for reuse
+        return tests.DatabaseBaseTests.create_database(self, replica_uid)
+
+    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 assertLastExchangeLog(self, db, expected):
+        log = getattr(db, '_last_exchange_log', None)
+        if log is None:
+            return
+        self.assertEqual(expected, log)
+
+    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 = tests.DatabaseBaseTests.copy_database(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 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):
+        """
+        Test for sync autoresolve remote.
+
+        This test was adapted because the remote database receives encrypted
+        content and so it can't compare documents contents to autoresolve.
+        """
+        # The remote database can't autoresolve conflicts based on magic
+        # content convergence, so we modify this test to leave the possibility
+        # of the remode document ending up in conflicted state.
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        doc1 = self.db1.create_doc_from_json(tests.simple_doc, doc_id='doc')
+        rev1 = doc1.rev
+        doc2 = self.db2.create_doc_from_json(tests.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)
+        # if remote content is in conflicted state, then document revisions
+        # will be different.
+        # 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):
+        """
+        Test for sync autoresolve local.
+
+        This test was adapted to decrypt remote content before assert.
+        """
+        # 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(tests.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
+        doc1 = self.db1.get_doc('doc')
+        self.assertGetEncryptedDoc(
+            self.db2,
+            doc1.doc_id, doc1.rev, doc1.get_json(), False)
+
+    def test_sync_autoresolves_moar_backwards(self):
+        # here we would 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.
+        #
+        # Despite that, in Soledad we suppose that the server never syncs, so
+        # it never has conflicted documents. Also, if it had, convergence
+        # would not be possible by checking document's contents because they
+        # would be encrypted in server.
+        #
+        # Therefore we suppress this test.
+        pass
+
+    def test_sync_autoresolves_moar_backwards_three(self):
+        # here we would 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.
+        #
+        # We use the same reasoning from the last test to suppress this one.
+        pass
+
+    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(tests.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(tests.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(tests.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(tests.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(tests.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(tests.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(tests.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(tests.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(tests.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_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_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(
+            errors.InvalidReplicaUID, self.sync, self.db1, self.db2)
+
+    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())
+
+    def test_sync_propagates_resolution(self):
+        """
+        Test if synchronization propagates resolution.
+
+        This test was adapted to decrypt remote content before assert.
+        """
+        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)
+        self.db1.close()
+        self.db2.close()
+        db3.close()
+
+    def test_sync_puts_changes(self):
+        """
+        Test if sync puts changes in remote replica.
+
+        This test was adapted to decrypt remote content before assert.
+        """
+        self.db1 = self.create_database('test1', 'source')
+        self.db2 = self.create_database('test2', 'target')
+        doc = self.db1.create_doc_from_json(tests.simple_doc)
+        self.assertEqual(1, self.sync(self.db1, self.db2))
+        self.assertGetEncryptedDoc(
+            self.db2, doc.doc_id, doc.rev, tests.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(tests.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,
+                          tests.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_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_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(
+            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(
+            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(
+            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(
+            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(
+            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(
+            errors.InvalidTransactionId, self.sync, self.db1, self.db2_copy)
+
+
+def make_local_db_and_soledad_target(
+        test, path='test',
+        source_replica_uid=uuid4().hex):
+    test.startTwistedServer()
+    replica_uid = os.path.basename(path)
+    db = test.request_state._create_database(replica_uid)
+    st = soledad_sync_target(
+        test, db._dbname,
+        source_replica_uid=source_replica_uid)
+    return db, st
+
+
+target_scenarios = [
+    ('leap', {
+        'create_db_and_target': make_local_db_and_soledad_target,
+        'make_app_with_state': make_soledad_app,
+        'do_sync': sync_via_synchronizer_and_soledad}),
+]
diff --git a/tests/sync/test_sync.py b/tests/sync/test_sync.py
new file mode 100644
index 00000000..fb9a0245
--- /dev/null
+++ b/tests/sync/test_sync.py
@@ -0,0 +1,233 @@
+# -*- coding: utf-8 -*-
+# test_sync.py
+# Copyright (C) 2013, 2014 LEAP
+#
+# 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 3 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, see <http://www.gnu.org/licenses/>.
+import json
+import pytest
+import threading
+import time
+
+from six.moves.urllib.parse import urljoin
+from mock import Mock
+from twisted.internet import defer
+
+from testscenarios import TestWithScenarios
+
+from leap.soledad.common import couch
+from leap.soledad.client import sync
+
+from test_soledad import u1db_tests as tests
+from test_soledad.u1db_tests import TestCaseWithServer
+from test_soledad.u1db_tests import simple_doc
+from test_soledad.util import make_token_soledad_app
+from test_soledad.util import make_soledad_document_for_test
+from test_soledad.util import soledad_sync_target
+from test_soledad.util import BaseSoledadTest
+from test_soledad.util import SoledadWithCouchServerMixin
+from test_soledad.util import CouchDBTestCase
+
+
+class InterruptableSyncTestCase(
+        BaseSoledadTest, CouchDBTestCase, TestCaseWithServer):
+
+    """
+    Tests for encrypted sync using Soledad server backed by a couch database.
+    """
+
+    @staticmethod
+    def make_app_with_state(state):
+        return make_token_soledad_app(state)
+
+    make_document_for_test = make_soledad_document_for_test
+
+    sync_target = soledad_sync_target
+
+    def make_app(self):
+        self.request_state = couch.CouchServerState(self.couch_url)
+        return self.make_app_with_state(self.request_state)
+
+    def setUp(self):
+        TestCaseWithServer.setUp(self)
+        CouchDBTestCase.setUp(self)
+
+    def tearDown(self):
+        CouchDBTestCase.tearDown(self)
+        TestCaseWithServer.tearDown(self)
+
+    def test_interruptable_sync(self):
+        """
+        Test if Soledad can sync many smallfiles.
+        """
+
+        self.skipTest("Sync is currently not interruptable.")
+
+        class _SyncInterruptor(threading.Thread):
+
+            """
+            A thread meant to interrupt the sync process.
+            """
+
+            def __init__(self, soledad, couchdb):
+                self._soledad = soledad
+                self._couchdb = couchdb
+                threading.Thread.__init__(self)
+
+            def run(self):
+                while db._get_generation() < 2:
+                    # print "WAITING %d" % db._get_generation()
+                    time.sleep(0.1)
+                self._soledad.stop_sync()
+                time.sleep(1)
+
+        number_of_docs = 10
+        self.startServer()
+
+        # instantiate soledad and create a document
+        sol = self._soledad_instance(
+            user='user-uuid', server_url=self.getURL())
+
+        # ensure remote db exists before syncing
+        db = couch.CouchDatabase.open_database(
+            urljoin(self.couch_url, 'user-user-uuid'),
+            create=True)
+
+        # create interruptor thread
+        t = _SyncInterruptor(sol, db)
+        t.start()
+
+        d = sol.get_all_docs()
+        d.addCallback(lambda results: self.assertEqual([], results[1]))
+
+        def _create_docs(results):
+            # create many small files
+            deferreds = []
+            for i in range(0, number_of_docs):
+                deferreds.append(sol.create_doc(json.loads(simple_doc)))
+            return defer.DeferredList(deferreds)
+
+        # sync with server
+        d.addCallback(_create_docs)
+        d.addCallback(lambda _: sol.get_all_docs())
+        d.addCallback(
+            lambda results: self.assertEqual(number_of_docs, len(results[1])))
+        d.addCallback(lambda _: sol.sync())
+        d.addCallback(lambda _: t.join())
+        d.addCallback(lambda _: db.get_all_docs())
+        d.addCallback(
+            lambda results: self.assertNotEqual(
+                number_of_docs, len(results[1])))
+        d.addCallback(lambda _: sol.sync())
+        d.addCallback(lambda _: db.get_all_docs())
+        d.addCallback(
+            lambda results: self.assertEqual(number_of_docs, len(results[1])))
+
+        def _tear_down(results):
+            db.delete_database()
+            db.close()
+            sol.close()
+
+        d.addCallback(_tear_down)
+        return d
+
+
+@pytest.mark.needs_couch
+class TestSoledadDbSync(
+        TestWithScenarios,
+        SoledadWithCouchServerMixin,
+        tests.TestCaseWithServer):
+
+    """
+    Test db.sync remote sync shortcut
+    """
+
+    scenarios = [
+        ('py-token-http', {
+            'make_app_with_state': make_token_soledad_app,
+            'make_database_for_test': tests.make_memory_database_for_test,
+            'token': True
+        }),
+    ]
+
+    oauth = False
+    token = False
+
+    def setUp(self):
+        """
+        Need to explicitely invoke inicialization on all bases.
+        """
+        SoledadWithCouchServerMixin.setUp(self)
+        self.startTwistedServer()
+        self.db = self.make_database_for_test(self, 'test1')
+        self.db2 = self.request_state._create_database(replica_uid='test')
+
+    def tearDown(self):
+        """
+        Need to explicitely invoke destruction on all bases.
+        """
+        SoledadWithCouchServerMixin.tearDown(self)
+        # tests.TestCaseWithServer.tearDown(self)
+
+    def do_sync(self):
+        """
+        Perform sync using SoledadSynchronizer, SoledadSyncTarget
+        and Token auth.
+        """
+        target = soledad_sync_target(
+            self, self.db2._dbname,
+            source_replica_uid=self._soledad._dbpool.replica_uid)
+        return sync.SoledadSynchronizer(
+            self.db,
+            target).sync()
+
+    @defer.inlineCallbacks
+    def test_db_sync(self):
+        """
+        Test sync.
+
+        Adapted to check for encrypted content.
+        """
+
+        doc1 = self.db.create_doc_from_json(tests.simple_doc)
+        doc2 = self.db2.create_doc_from_json(tests.nested_doc)
+
+        local_gen_before_sync = yield self.do_sync()
+        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.assertGetEncryptedDoc(
+            self.db2, doc1.doc_id, doc1.rev, tests.simple_doc, False)
+        self.assertGetEncryptedDoc(
+            self.db, doc2.doc_id, doc2.rev, tests.nested_doc, False)
+
+    # TODO: add u1db.tests.test_sync.TestRemoteSyncIntegration
+
+
+class TestSoledadSynchronizer(BaseSoledadTest):
+
+    def setUp(self):
+        BaseSoledadTest.setUp(self)
+        self.db = Mock()
+        self.target = Mock()
+        self.synchronizer = sync.SoledadSynchronizer(
+            self.db,
+            self.target)
+
+    def test_docs_by_gen_includes_deleted(self):
+        changes = [('id', 'gen', 'trans')]
+        docs_by_gen = self.synchronizer._docs_by_gen_from_changes(changes)
+        f, args, kwargs = docs_by_gen[0][0]
+        self.assertIn('include_deleted', kwargs)
+        self.assertTrue(kwargs['include_deleted'])
diff --git a/tests/sync/test_sync_mutex.py b/tests/sync/test_sync_mutex.py
new file mode 100644
index 00000000..fdd2aacd
--- /dev/null
+++ b/tests/sync/test_sync_mutex.py
@@ -0,0 +1,133 @@
+# -*- coding: utf-8 -*-
+# test_sync_mutex.py
+# Copyright (C) 2013, 2014 LEAP
+#
+# 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 3 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, see <http://www.gnu.org/licenses/>.
+
+
+"""
+Test that synchronization is a critical section and, as such, there might not
+be two concurrent synchronization processes at the same time.
+"""
+
+
+import pytest
+import time
+import uuid
+
+from six.moves.urllib.parse import urljoin
+
+from twisted.internet import defer
+
+from leap.soledad.client.sync import SoledadSynchronizer
+
+from leap.soledad.common.couch.state import CouchServerState
+from leap.soledad.common.couch import CouchDatabase
+from test_soledad.u1db_tests import TestCaseWithServer
+
+from test_soledad.util import CouchDBTestCase
+from test_soledad.util import BaseSoledadTest
+from test_soledad.util import make_token_soledad_app
+from test_soledad.util import make_soledad_document_for_test
+from test_soledad.util import soledad_sync_target
+
+
+# monkey-patch the soledad synchronizer so it stores start and finish times
+
+_old_sync = SoledadSynchronizer.sync
+
+
+def _timed_sync(self):
+    t = time.time()
+
+    sync_id = uuid.uuid4()
+
+    if not getattr(self.source, 'sync_times', False):
+        self.source.sync_times = {}
+
+    self.source.sync_times[sync_id] = {'start': t}
+
+    def _store_finish_time(passthrough):
+        t = time.time()
+        self.source.sync_times[sync_id]['end'] = t
+        return passthrough
+
+    d = _old_sync(self)
+    d.addBoth(_store_finish_time)
+    return d
+
+
+SoledadSynchronizer.sync = _timed_sync
+
+# -- end of monkey-patching
+
+
+@pytest.mark.needs_couch
+class TestSyncMutex(
+        BaseSoledadTest, CouchDBTestCase, TestCaseWithServer):
+
+    @staticmethod
+    def make_app_with_state(state):
+        return make_token_soledad_app(state)
+
+    make_document_for_test = make_soledad_document_for_test
+
+    sync_target = soledad_sync_target
+
+    def make_app(self):
+        self.request_state = CouchServerState(self.couch_url)
+        return self.make_app_with_state(self.request_state)
+
+    def setUp(self):
+        TestCaseWithServer.setUp(self)
+        CouchDBTestCase.setUp(self)
+        self.user = ('user-%s' % uuid.uuid4().hex)
+
+    def tearDown(self):
+        CouchDBTestCase.tearDown(self)
+        TestCaseWithServer.tearDown(self)
+
+    def test_two_concurrent_syncs_do_not_overlap_no_docs(self):
+        self.startServer()
+
+        # ensure remote db exists before syncing
+        db = CouchDatabase.open_database(
+            urljoin(self.couch_url, 'user-' + self.user),
+            create=True)
+
+        sol = self._soledad_instance(
+            user=self.user, server_url=self.getURL())
+
+        d1 = sol.sync()
+        d2 = sol.sync()
+
+        def _assert_syncs_do_not_overlap(thearg):
+            # recover sync times
+            sync_times = []
+            for key in sol._dbsyncer.sync_times:
+                sync_times.append(sol._dbsyncer.sync_times[key])
+            sync_times.sort(key=lambda s: s['start'])
+
+            self.assertTrue(
+                (sync_times[0]['start'] < sync_times[0]['end'] and
+                 sync_times[0]['end'] < sync_times[1]['start'] and
+                 sync_times[1]['start'] < sync_times[1]['end']))
+
+            db.delete_database()
+            db.close()
+            sol.close()
+
+        d = defer.gatherResults([d1, d2])
+        d.addBoth(_assert_syncs_do_not_overlap)
+        return d
diff --git a/tests/sync/test_sync_target.py b/tests/sync/test_sync_target.py
new file mode 100644
index 00000000..712f0d3f
--- /dev/null
+++ b/tests/sync/test_sync_target.py
@@ -0,0 +1,968 @@
+# -*- coding: utf-8 -*-
+# test_sync_target.py
+# Copyright (C) 2013, 2014 LEAP
+#
+# 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 3 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, see <http://www.gnu.org/licenses/>.
+"""
+Test Leap backend bits: sync target
+"""
+import os
+import time
+import json
+import pytest
+import random
+import string
+import shutil
+
+from six import StringIO as cStringIO
+from uuid import uuid4
+
+from testscenarios import TestWithScenarios
+from twisted.internet import defer
+
+from leap.soledad.client import http_target as target
+from leap.soledad.client.http_target.fetch_protocol import DocStreamReceiver
+from leap.soledad.client._db.sqlcipher import SQLCipherU1DBSync
+from leap.soledad.client._db.sqlcipher import SQLCipherOptions
+from leap.soledad.client._db.sqlcipher import SQLCipherDatabase
+from leap.soledad.client import _crypto
+
+from leap.soledad.common import l2db
+
+from leap.soledad.common.document import SoledadDocument
+from test_soledad import u1db_tests as tests
+from test_soledad.util import make_sqlcipher_database_for_test
+from test_soledad.util import make_soledad_app
+from test_soledad.util import make_token_soledad_app
+from test_soledad.util import make_soledad_document_for_test
+from test_soledad.util import soledad_sync_target
+from twisted.trial import unittest
+from test_soledad.util import SoledadWithCouchServerMixin
+from test_soledad.util import ADDRESS
+from test_soledad.util import SQLCIPHER_SCENARIOS
+
+
+# -----------------------------------------------------------------------------
+# The following tests come from `u1db.tests.test_remote_sync_target`.
+# -----------------------------------------------------------------------------
+
+class TestSoledadParseReceivedDocResponse(unittest.TestCase):
+
+    """
+    Some tests had to be copied to this class so we can instantiate our own
+    target.
+    """
+
+    def parse(self, stream):
+        parser = DocStreamReceiver(None, defer.Deferred(),
+                                   lambda *_: defer.succeed(42))
+        parser.dataReceived(stream)
+        parser.finish()
+
+    def test_extra_comma(self):
+        doc = SoledadDocument('i', rev='r')
+        doc.content = {'a': 'b'}
+
+        encrypted_docstr = _crypto.SoledadCrypto('safe').encrypt_doc(doc)
+
+        with self.assertRaises(l2db.errors.BrokenSyncStream):
+            self.parse("[\r\n{},\r\n]")
+
+        with self.assertRaises(l2db.errors.BrokenSyncStream):
+            self.parse(
+                ('[\r\n{},\r\n{"id": "i", "rev": "r", ' +
+                 '"gen": 3, "trans_id": "T-sid"},\r\n' +
+                 '%s,\r\n]') % encrypted_docstr)
+
+    def test_wrong_start(self):
+        with self.assertRaises(l2db.errors.BrokenSyncStream):
+            self.parse("{}\r\n]")
+
+        with self.assertRaises(l2db.errors.BrokenSyncStream):
+            self.parse("\r\n{}\r\n]")
+
+    def test_wrong_end(self):
+        with self.assertRaises(l2db.errors.BrokenSyncStream):
+            self.parse("[\r\n{}")
+
+        with self.assertRaises(l2db.errors.BrokenSyncStream):
+            self.parse("[\r\n")
+
+    def test_missing_comma(self):
+        with self.assertRaises(l2db.errors.BrokenSyncStream):
+            self.parse(
+                '[\r\n{}\r\n{"id": "i", "rev": "r", '
+                '"content": "c", "gen": 3}\r\n]')
+
+    def test_no_entries(self):
+        with self.assertRaises(l2db.errors.BrokenSyncStream):
+            self.parse("[\r\n]")
+
+    def test_error_in_stream(self):
+        with self.assertRaises(l2db.errors.BrokenSyncStream):
+            self.parse(
+                '[\r\n{"new_generation": 0},'
+                '\r\n{"error": "unavailable"}\r\n')
+
+        with self.assertRaises(l2db.errors.BrokenSyncStream):
+            self.parse(
+                '[\r\n{"error": "unavailable"}\r\n')
+
+        with self.assertRaises(l2db.errors.BrokenSyncStream):
+            self.parse('[\r\n{"error": "?"}\r\n')
+
+#
+# functions for TestRemoteSyncTargets
+#
+
+
+def make_local_db_and_soledad_target(
+        test, path='test',
+        source_replica_uid=uuid4().hex):
+    test.startTwistedServer()
+    replica_uid = os.path.basename(path)
+    db = test.request_state._create_database(replica_uid)
+    st = soledad_sync_target(
+        test, db._dbname,
+        source_replica_uid=source_replica_uid)
+    return db, st
+
+
+def make_local_db_and_token_soledad_target(
+        test,
+        source_replica_uid=uuid4().hex):
+    db, st = make_local_db_and_soledad_target(
+        test, path='test',
+        source_replica_uid=source_replica_uid)
+    st.set_token_credentials('user-uuid', 'auth-token')
+    return db, st
+
+
+@pytest.mark.needs_couch
+class TestSoledadSyncTarget(
+        TestWithScenarios,
+        SoledadWithCouchServerMixin,
+        tests.TestCaseWithServer):
+
+    scenarios = [
+        ('token_soledad',
+            {'make_app_with_state': make_token_soledad_app,
+             'make_document_for_test': make_soledad_document_for_test,
+             'create_db_and_target': make_local_db_and_token_soledad_target,
+             'make_database_for_test': make_sqlcipher_database_for_test,
+             'sync_target': soledad_sync_target}),
+    ]
+
+    def getSyncTarget(self, path=None, source_replica_uid=uuid4().hex):
+        if self.port is None:
+            self.startTwistedServer()
+        if path is None:
+            path = self.db2._dbname
+        target = self.sync_target(
+            self, path,
+            source_replica_uid=source_replica_uid)
+        return target
+
+    def setUp(self):
+        TestWithScenarios.setUp(self)
+        SoledadWithCouchServerMixin.setUp(self)
+        self.startTwistedServer()
+        self.db1 = make_sqlcipher_database_for_test(self, 'test1')
+        self.db2 = self.request_state._create_database('test')
+
+    def tearDown(self):
+        # db2, _ = self.request_state.ensure_database('test2')
+        self.delete_db(self.db2._dbname)
+        self.db1.close()
+        SoledadWithCouchServerMixin.tearDown(self)
+        TestWithScenarios.tearDown(self)
+
+    @defer.inlineCallbacks
+    def test_sync_exchange_send(self):
+        """
+        Test for sync exchanging send of document.
+
+        This test was adapted to decrypt remote content before assert.
+        """
+        db = self.db2
+        remote_target = self.getSyncTarget()
+        other_docs = []
+
+        def receive_doc(doc, gen, trans_id):
+            other_docs.append((doc.doc_id, doc.rev, doc.get_json()))
+
+        doc = self.make_document('doc-here', 'replica:1', '{"value": "here"}')
+        get_doc = (lambda _: doc, (1,), {})
+        new_gen, trans_id = yield remote_target.sync_exchange(
+            [(get_doc, 10, 'T-sid')], 'replica', last_known_generation=0,
+            last_known_trans_id=None, insert_doc_cb=receive_doc)
+        self.assertEqual(1, new_gen)
+        self.assertGetEncryptedDoc(
+            db, 'doc-here', 'replica:1', '{"value": "here"}', False)
+
+    @defer.inlineCallbacks
+    def test_sync_exchange_send_failure_and_retry_scenario(self):
+        """
+        Test for sync exchange failure and retry.
+
+        This test was adapted to decrypt remote content before assert.
+        """
+
+        def blackhole_getstderr(inst):
+            return cStringIO.StringIO()
+
+        db = self.db2
+        _put_doc_if_newer = db._put_doc_if_newer
+        trigger_ids = ['doc-here2']
+
+        def bomb_put_doc_if_newer(self, doc, save_conflict,
+                                  replica_uid=None, replica_gen=None,
+                                  replica_trans_id=None, number_of_docs=None,
+                                  doc_idx=None, sync_id=None):
+            if doc.doc_id in trigger_ids:
+                raise l2db.errors.U1DBError
+            return _put_doc_if_newer(doc, save_conflict=save_conflict,
+                                     replica_uid=replica_uid,
+                                     replica_gen=replica_gen,
+                                     replica_trans_id=replica_trans_id,
+                                     number_of_docs=number_of_docs,
+                                     doc_idx=doc_idx, sync_id=sync_id)
+        from leap.soledad.common.backend import SoledadBackend
+        self.patch(
+            SoledadBackend, '_put_doc_if_newer', bomb_put_doc_if_newer)
+        remote_target = self.getSyncTarget(
+            source_replica_uid='replica')
+        other_changes = []
+
+        def receive_doc(doc, gen, trans_id):
+            other_changes.append(
+                (doc.doc_id, doc.rev, doc.get_json(), gen, trans_id))
+
+        doc1 = self.make_document('doc-here', 'replica:1', '{"value": "here"}')
+        doc2 = self.make_document('doc-here2', 'replica:1',
+                                  '{"value": "here2"}')
+        get_doc1 = (lambda _: doc1, (1,), {})
+        get_doc2 = (lambda _: doc2, (2,), {})
+
+        with self.assertRaises(l2db.errors.U1DBError):
+            yield remote_target.sync_exchange(
+                [(get_doc1, 10, 'T-sid'), (get_doc2, 11, 'T-sud')],
+                'replica',
+                last_known_generation=0,
+                last_known_trans_id=None,
+                insert_doc_cb=receive_doc)
+
+        self.assertGetEncryptedDoc(
+            db, 'doc-here', 'replica:1', '{"value": "here"}',
+            False)
+        self.assertEqual(
+            (10, 'T-sid'), db._get_replica_gen_and_trans_id('replica'))
+        self.assertEqual([], other_changes)
+        # retry
+        trigger_ids = []
+        new_gen, trans_id = yield remote_target.sync_exchange(
+            [(get_doc2, 11, 'T-sud')], 'replica', last_known_generation=0,
+            last_known_trans_id=None, insert_doc_cb=receive_doc)
+        self.assertGetEncryptedDoc(
+            db, 'doc-here2', 'replica:1', '{"value": "here2"}',
+            False)
+        self.assertEqual(
+            (11, 'T-sud'), db._get_replica_gen_and_trans_id('replica'))
+        self.assertEqual(2, new_gen)
+        self.assertEqual(
+            ('doc-here', 'replica:1', '{"value": "here"}', 1),
+            other_changes[0][:-1])
+
+    @defer.inlineCallbacks
+    def test_sync_exchange_send_ensure_callback(self):
+        """
+        Test for sync exchange failure and retry.
+
+        This test was adapted to decrypt remote content before assert.
+        """
+        remote_target = self.getSyncTarget()
+        other_docs = []
+        replica_uid_box = []
+
+        def receive_doc(doc, gen, trans_id):
+            other_docs.append((doc.doc_id, doc.rev, doc.get_json()))
+
+        def ensure_cb(replica_uid):
+            replica_uid_box.append(replica_uid)
+
+        doc = self.make_document('doc-here', 'replica:1', '{"value": "here"}')
+        get_doc = (lambda _: doc, (1,), {})
+        new_gen, trans_id = yield remote_target.sync_exchange(
+            [(get_doc, 10, 'T-sid')], 'replica', last_known_generation=0,
+            last_known_trans_id=None, insert_doc_cb=receive_doc,
+            ensure_callback=ensure_cb)
+        self.assertEqual(1, new_gen)
+        db = self.db2
+        self.assertEqual(1, len(replica_uid_box))
+        self.assertEqual(db._replica_uid, replica_uid_box[0])
+        self.assertGetEncryptedDoc(
+            db, 'doc-here', 'replica:1', '{"value": "here"}', False)
+
+    @defer.inlineCallbacks
+    def test_sync_exchange_send_events(self):
+        """
+        Test for sync exchange's SOLEDAD_SYNC_SEND_STATUS event.
+        """
+        remote_target = self.getSyncTarget()
+        uuid = remote_target.uuid
+        events = []
+
+        def mocked_events(*args):
+            events.append((args))
+        self.patch(
+            target.send, '_emit_send_status', mocked_events)
+
+        doc = self.make_document('doc-here', 'replica:1', '{"value": "here"}')
+        doc2 = self.make_document('doc-here', 'replica:1', '{"value": "here"}')
+        doc3 = self.make_document('doc-here', 'replica:1', '{"value": "here"}')
+        get_doc = (lambda _: doc, (1,), {})
+        get_doc2 = (lambda _: doc2, (1,), {})
+        get_doc3 = (lambda _: doc3, (1,), {})
+        docs = [(get_doc, 10, 'T-sid'),
+                (get_doc2, 11, 'T-sid2'), (get_doc3, 12, 'T-sid3')]
+        new_gen, trans_id = yield remote_target.sync_exchange(
+            docs, 'replica', last_known_generation=0,
+            last_known_trans_id=None, insert_doc_cb=lambda _: 1,
+            ensure_callback=lambda _: 1)
+        self.assertEqual(1, new_gen)
+        self.assertEqual(4, len(events))
+        self.assertEquals([(uuid, 0, 3), (uuid, 1, 3), (uuid, 2, 3),
+                           (uuid, 3, 3)], events)
+
+    def test_sync_exchange_in_stream_error(self):
+        self.skipTest("bypass this test because our sync_exchange process "
+                      "does not return u1db error 503 \"unavailable\" for "
+                      "now")
+
+    @defer.inlineCallbacks
+    def test_get_sync_info(self):
+        db = self.db2
+        db._set_replica_gen_and_trans_id('other-id', 1, 'T-transid')
+        remote_target = self.getSyncTarget(
+            source_replica_uid='other-id')
+        sync_info = yield remote_target.get_sync_info('other-id')
+        self.assertEqual(
+            ('test', 0, '', 1, 'T-transid'),
+            sync_info)
+
+    @defer.inlineCallbacks
+    def test_record_sync_info(self):
+        remote_target = self.getSyncTarget(
+            source_replica_uid='other-id')
+        yield remote_target.record_sync_info('other-id', 2, 'T-transid')
+        self.assertEqual((2, 'T-transid'),
+                         self.db2._get_replica_gen_and_trans_id('other-id'))
+
+    @defer.inlineCallbacks
+    def test_sync_exchange_receive(self):
+        db = self.db2
+        doc = db.create_doc_from_json('{"value": "there"}')
+        remote_target = self.getSyncTarget()
+        other_changes = []
+
+        def receive_doc(doc, gen, trans_id):
+            other_changes.append(
+                (doc.doc_id, doc.rev, doc.get_json(), gen, trans_id))
+
+        new_gen, trans_id = yield remote_target.sync_exchange(
+            [], 'replica', last_known_generation=0, last_known_trans_id=None,
+            insert_doc_cb=receive_doc)
+        self.assertEqual(1, new_gen)
+        self.assertEqual(
+            (doc.doc_id, doc.rev, '{"value": "there"}', 1),
+            other_changes[0][:-1])
+
+
+# -----------------------------------------------------------------------------
+# The following tests come from `u1db.tests.test_sync`.
+# -----------------------------------------------------------------------------
+
+target_scenarios = [
+    ('mem,token_soledad',
+     {'create_db_and_target': make_local_db_and_token_soledad_target,
+      'make_app_with_state': make_soledad_app,
+      'make_database_for_test': tests.make_memory_database_for_test,
+      'copy_database_for_test': tests.copy_memory_database_for_test,
+      'make_document_for_test': tests.make_document_for_test})
+]
+
+
+@pytest.mark.needs_couch
+class SoledadDatabaseSyncTargetTests(
+        TestWithScenarios,
+        SoledadWithCouchServerMixin,
+        tests.DatabaseBaseTests,
+        tests.TestCaseWithServer):
+    """
+    Adaptation of u1db.tests.test_sync.DatabaseSyncTargetTests.
+    """
+
+    # TODO: implement _set_trace_hook(_shallow) in SoledadHTTPSyncTarget so
+    #       skipped tests can be succesfully executed.
+
+    scenarios = target_scenarios
+
+    whitebox = False
+
+    def setUp(self):
+        tests.TestCaseWithServer.setUp(self)
+        self.other_changes = []
+        SoledadWithCouchServerMixin.setUp(self)
+        self.db, self.st = make_local_db_and_soledad_target(self)
+
+    def tearDown(self):
+        self.db.close()
+        tests.TestCaseWithServer.tearDown(self)
+        SoledadWithCouchServerMixin.tearDown(self)
+
+    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__,))
+
+    @defer.inlineCallbacks
+    def test_sync_exchange(self):
+        """
+        Test sync exchange.
+
+        This test was adapted to decrypt remote content before assert.
+        """
+        docs_by_gen = [
+            ((self.make_document,
+              ('doc-id', 'replica:1', tests.simple_doc,), {}),
+                10, 'T-sid')]
+        new_gen, trans_id = yield self.st.sync_exchange(
+            docs_by_gen, 'replica', last_known_generation=0,
+            last_known_trans_id=None, insert_doc_cb=self.receive_doc)
+        self.assertGetEncryptedDoc(
+            self.db, 'doc-id', 'replica:1', tests.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))
+        sync_info = yield self.st.get_sync_info('replica')
+        self.assertEqual(10, sync_info[3])
+
+    @defer.inlineCallbacks
+    def test_sync_exchange_push_many(self):
+        """
+        Test sync exchange.
+
+        This test was adapted to decrypt remote content before assert.
+        """
+        docs_by_gen = [
+            ((self.make_document,
+                ('doc-id', 'replica:1', tests.simple_doc), {}), 10, 'T-1'),
+            ((self.make_document,
+                ('doc-id2', 'replica:1', tests.nested_doc), {}), 11, 'T-2')]
+        new_gen, trans_id = yield self.st.sync_exchange(
+            docs_by_gen, 'replica', last_known_generation=0,
+            last_known_trans_id=None, insert_doc_cb=self.receive_doc)
+        self.assertGetEncryptedDoc(
+            self.db, 'doc-id', 'replica:1', tests.simple_doc, False)
+        self.assertGetEncryptedDoc(
+            self.db, 'doc-id2', 'replica:1', tests.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))
+        sync_info = yield self.st.get_sync_info('replica')
+        self.assertEqual(11, sync_info[3])
+
+    @defer.inlineCallbacks
+    def test_sync_exchange_returns_many_new_docs(self):
+        """
+        Test sync exchange.
+
+        This test was adapted to avoid JSON serialization comparison as local
+        and remote representations might differ. It looks directly at the
+        doc's contents instead.
+        """
+        doc = self.db.create_doc_from_json(tests.simple_doc)
+        doc2 = self.db.create_doc_from_json(tests.nested_doc)
+        self.assertTransactionLog([doc.doc_id, doc2.doc_id], self.db)
+        new_gen, _ = yield self.st.sync_exchange(
+            [], 'other-replica', last_known_generation=0,
+            last_known_trans_id=None, insert_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, 1),
+             (doc2.doc_id, doc2.rev, 2)],
+            [c[:-3] + c[-2:-1] for c in self.other_changes])
+        self.assertEqual(
+            json.loads(tests.simple_doc),
+            json.loads(self.other_changes[0][2]))
+        self.assertEqual(
+            json.loads(tests.nested_doc),
+            json.loads(self.other_changes[1][2]))
+        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 receive_doc(self, doc, gen, trans_id):
+        self.other_changes.append(
+            (doc.doc_id, doc.rev, doc.get_json(), gen, trans_id))
+
+    def test_get_sync_target(self):
+        self.assertIsNot(None, self.st)
+
+    @defer.inlineCallbacks
+    def test_get_sync_info(self):
+        sync_info = yield self.st.get_sync_info('other')
+        self.assertEqual(
+            ('test', 0, '', 0, ''), sync_info)
+
+    @defer.inlineCallbacks
+    def test_create_doc_updates_sync_info(self):
+        sync_info = yield self.st.get_sync_info('other')
+        self.assertEqual(
+            ('test', 0, '', 0, ''), sync_info)
+        self.db.create_doc_from_json(tests.simple_doc)
+        sync_info = yield self.st.get_sync_info('other')
+        self.assertEqual(1, sync_info[1])
+
+    @defer.inlineCallbacks
+    def test_record_sync_info(self):
+        yield self.st.record_sync_info('replica', 10, 'T-transid')
+        sync_info = yield self.st.get_sync_info('replica')
+        self.assertEqual(
+            ('test', 0, '', 10, 'T-transid'), sync_info)
+
+    @defer.inlineCallbacks
+    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 = yield self.st.sync_exchange(
+            docs_by_gen, 'replica', last_known_generation=0,
+            last_known_trans_id=None, insert_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))
+        sync_info = yield self.st.get_sync_info('replica')
+        self.assertEqual(10, sync_info[3])
+
+    @defer.inlineCallbacks
+    def test_sync_exchange_refuses_conflicts(self):
+        doc = self.db.create_doc_from_json(tests.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, _ = yield self.st.sync_exchange(
+            docs_by_gen, 'replica', last_known_generation=0,
+            last_known_trans_id=None, insert_doc_cb=self.receive_doc)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        self.assertEqual(
+            (doc.doc_id, doc.rev, tests.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)]})
+
+    @defer.inlineCallbacks
+    def test_sync_exchange_ignores_convergence(self):
+        doc = self.db.create_doc_from_json(tests.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, tests.simple_doc), {}),
+             10, 'T-sid')]
+        new_gen, _ = yield self.st.sync_exchange(
+            docs_by_gen, 'replica', last_known_generation=gen,
+            last_known_trans_id=txid, insert_doc_cb=self.receive_doc)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        self.assertEqual(([], 1), (self.other_changes, new_gen))
+
+    @defer.inlineCallbacks
+    def test_sync_exchange_returns_new_docs(self):
+        doc = self.db.create_doc_from_json(tests.simple_doc)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        new_gen, _ = yield self.st.sync_exchange(
+            [], 'other-replica', last_known_generation=0,
+            last_known_trans_id=None, insert_doc_cb=self.receive_doc)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        self.assertEqual(
+            (doc.doc_id, doc.rev, tests.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)]})
+
+    @defer.inlineCallbacks
+    def test_sync_exchange_returns_deleted_docs(self):
+        doc = self.db.create_doc_from_json(tests.simple_doc)
+        self.db.delete_doc(doc)
+        self.assertTransactionLog([doc.doc_id, doc.doc_id], self.db)
+        new_gen, _ = yield self.st.sync_exchange(
+            [], 'other-replica', last_known_generation=0,
+            last_known_trans_id=None, insert_doc_cb=self.receive_doc)
+        self.assertTransactionLog([doc.doc_id, doc.doc_id], self.db)
+        self.assertEqual(2, new_gen)
+        self.assertEqual(
+            (doc.doc_id, doc.rev, None, 2), self.other_changes[0][:-1])
+        if self.whitebox:
+            self.assertEqual(self.db._last_exchange_log['return'],
+                             {'last_gen': 2, 'docs': [(doc.doc_id, doc.rev)]})
+
+    @defer.inlineCallbacks
+    def test_sync_exchange_getting_newer_docs(self):
+        doc = self.db.create_doc_from_json(tests.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, _ = yield self.st.sync_exchange(
+            docs_by_gen, 'other-replica', last_known_generation=0,
+            last_known_trans_id=None, insert_doc_cb=self.receive_doc)
+        self.assertTransactionLog([doc.doc_id, doc.doc_id], self.db)
+        self.assertEqual(([], 2), (self.other_changes, new_gen))
+
+    @defer.inlineCallbacks
+    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(tests.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, _ = yield self.st.sync_exchange(
+            docs_by_gen, 'other-replica', last_known_generation=0,
+            last_known_trans_id=None, insert_doc_cb=self.receive_doc)
+        self.assertEqual(expected, [c[:-1] for c in self.other_changes])
+        self.assertEqual(3, new_gen)
+
+    @defer.inlineCallbacks
+    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(tests.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, _ = yield self.st.sync_exchange(
+            docs_by_gen, 'other-replica', last_known_generation=0,
+            last_known_trans_id=None, insert_doc_cb=self.receive_doc)
+        self.assertEqual(([], 2), (self.other_changes, new_gen))
+
+    @defer.inlineCallbacks
+    def test_sync_exchange_converged_handling(self):
+        doc = self.db.create_doc_from_json(tests.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, _ = yield self.st.sync_exchange(
+            docs_by_gen, 'other-replica', last_known_generation=0,
+            last_known_trans_id=None, insert_doc_cb=self.receive_doc)
+        self.assertEqual(([], 2), (self.other_changes, new_gen))
+
+    @defer.inlineCallbacks
+    def test_sync_exchange_detect_incomplete_exchange(self):
+        def before_get_docs_explode(state):
+            if state != 'before get_docs':
+                return
+            raise l2db.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(tests.simple_doc)
+        self.assertTransactionLog([doc.doc_id], self.db)
+        self.assertRaises(
+            (l2db.errors.U1DBError, l2db.errors.BrokenSyncStream),
+            self.st.sync_exchange, [], 'other-replica',
+            last_known_generation=0, last_known_trans_id=None,
+            insert_doc_cb=self.receive_doc)
+
+    @defer.inlineCallbacks
+    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(tests.simple_doc)
+        new_gen, trans_id = yield sync_exchange_doc_ids(
+            db2, [(doc.doc_id, 10, 'T-sid')], 0, None,
+            insert_doc_cb=self.receive_doc)
+        self.assertGetDoc(self.db, doc.doc_id, doc.rev,
+                          tests.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])
+
+    @defer.inlineCallbacks
+    def test__set_trace_hook(self):
+        called = []
+
+        def cb(state):
+            called.append(state)
+
+        self.set_trace_hook(cb)
+        yield self.st.sync_exchange([], 'replica', 0, None, self.receive_doc)
+        yield self.st.record_sync_info('replica', 0, 'T-sid')
+        self.assertEqual(['before whats_changed',
+                          'after whats_changed',
+                          'before get_docs',
+                          'record_sync_info',
+                          ],
+                         called)
+
+    @defer.inlineCallbacks
+    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 ==
+                target.SoledadHTTPSyncTarget._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)
+        yield self.st.sync_exchange([], 'replica', 0, None, self.receive_doc)
+        yield self.st.record_sync_info('replica', 0, 'T-sid')
+        self.assertEqual(expected, called)
+
+
+WAIT_STEP = 1
+MAX_WAIT = 10
+DBPASS = "pass"
+
+
+class SyncTimeoutError(Exception):
+
+    """
+    Dummy exception to notify timeout during sync.
+    """
+    pass
+
+
+@pytest.mark.needs_couch
+class TestSoledadDbSync(
+        TestWithScenarios,
+        SoledadWithCouchServerMixin,
+        tests.TestCaseWithServer):
+
+    """Test db.sync remote sync shortcut"""
+
+    scenarios = [
+        ('py-token-http', {
+            'create_db_and_target': make_local_db_and_token_soledad_target,
+            'make_app_with_state': make_token_soledad_app,
+            'make_database_for_test': make_sqlcipher_database_for_test,
+            'token': True
+        }),
+    ]
+
+    oauth = False
+    token = False
+
+    def setUp(self):
+        """
+        Need to explicitely invoke inicialization on all bases.
+        """
+        SoledadWithCouchServerMixin.setUp(self)
+        self.server = self.server_thread = None
+        self.startTwistedServer()
+        self.syncer = None
+
+        # config info
+        self.db1_file = os.path.join(self.tempdir, "db1.u1db")
+        os.unlink(self.db1_file)
+        self.db_pass = DBPASS
+        self.email = ADDRESS
+
+        # get a random prefix for each test, so we do not mess with
+        # concurrency during initialization and shutting down of
+        # each local db.
+        self.rand_prefix = ''.join(
+            map(lambda x: random.choice(string.ascii_letters), range(6)))
+
+        # open test dbs: db1 will be the local sqlcipher db (which
+        # instantiates a syncdb). We use the self._soledad instance that was
+        # already created on some setUp method.
+        import binascii
+        tohex = binascii.b2a_hex
+        key = tohex(self._soledad.secrets.local_key)
+        dbpath = self._soledad._local_db_path
+
+        self.opts = SQLCipherOptions(
+            dbpath, key, is_raw_key=True, create=False)
+        self.db1 = SQLCipherDatabase(self.opts)
+
+        self.db2 = self.request_state._create_database(replica_uid='test')
+
+    def tearDown(self):
+        """
+        Need to explicitely invoke destruction on all bases.
+        """
+        dbsyncer = getattr(self, 'dbsyncer', None)
+        if dbsyncer:
+            dbsyncer.close()
+        self.db1.close()
+        self.db2.close()
+        self._soledad.close()
+
+        # XXX should not access "private" attrs
+        shutil.rmtree(os.path.dirname(self._soledad._local_db_path))
+        SoledadWithCouchServerMixin.tearDown(self)
+
+    def do_sync(self, target_name):
+        """
+        Perform sync using SoledadSynchronizer, SoledadSyncTarget
+        and Token auth.
+        """
+        if self.token:
+            creds = {'token': {
+                'uuid': 'user-uuid',
+                'token': 'auth-token',
+            }}
+            target_url = self.getURL(self.db2._dbname)
+
+            # get a u1db syncer
+            crypto = self._soledad._crypto
+            replica_uid = self.db1._replica_uid
+            dbsyncer = SQLCipherU1DBSync(
+                self.opts,
+                crypto,
+                replica_uid,
+                None)
+            self.dbsyncer = dbsyncer
+            return dbsyncer.sync(target_url,
+                                 creds=creds)
+        else:
+            return self._do_sync(self, target_name)
+
+    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 wait_for_sync(self):
+        """
+        Wait for sync to finish.
+        """
+        wait = 0
+        syncer = self.syncer
+        if syncer is not None:
+            while syncer.syncing:
+                time.sleep(WAIT_STEP)
+                wait += WAIT_STEP
+                if wait >= MAX_WAIT:
+                    raise SyncTimeoutError
+
+    def test_db_sync(self):
+        """
+        Test sync.
+
+        Adapted to check for encrypted content.
+        """
+        doc1 = self.db1.create_doc_from_json(tests.simple_doc)
+        doc2 = self.db2.create_doc_from_json(tests.nested_doc)
+        d = self.do_sync('test')
+
+        def _assert_successful_sync(results):
+            import time
+            # need to give time to the encryption to proceed
+            # TODO should implement a defer list to subscribe to the
+            # all-decrypted event
+            time.sleep(2)
+            local_gen_before_sync = results
+            self.wait_for_sync()
+
+            gen, _, changes = self.db1.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.assertGetEncryptedDoc(
+                self.db2, doc1.doc_id, doc1.rev, tests.simple_doc, False)
+            self.assertGetEncryptedDoc(
+                self.db1, doc2.doc_id, doc2.rev, tests.nested_doc, False)
+
+        d.addCallback(_assert_successful_sync)
+        return d
+
+
+@pytest.mark.needs_couch
+class SQLCipherSyncTargetTests(SoledadDatabaseSyncTargetTests):
+
+    # TODO: implement _set_trace_hook(_shallow) in SoledadHTTPSyncTarget so
+    #       skipped tests can be succesfully executed.
+
+    scenarios = (tests.multiply_scenarios(SQLCIPHER_SCENARIOS,
+                                          target_scenarios))
+
+    whitebox = False