fix export: write backup_time to the destination not the source sql file

and perform slightly cleaner teardown in python

python/src/deltachat/account.py

@@ -153,6 +153,14 @@ class Account(object):
         self.check_is_configured()
         return from_dc_charpointer(lib.dc_get_info(self._dc_context))
 
+    def get_latest_backupfile(self, backupdir):
+        """ return the latest backup file in a given directory.
+        """
+        res = lib.dc_imex_has_backup(self._dc_context, as_dc_charpointer(backupdir))
+        if res == ffi.NULL:
+            return None
+        return from_dc_charpointer(res)
+
     def get_blobdir(self):
         """ return the directory for files.
 
@@ -477,8 +485,9 @@ class Account(object):
 
     def stop_threads(self, wait=True):
         """ stop IMAP/SMTP threads. """
-        self.stop_ongoing()
-        self._threads.stop(wait=wait)
+        if self._threads.is_started():
+            self.stop_ongoing()
+            self._threads.stop(wait=wait)
 
     def shutdown(self, wait=True):
         """ stop threads and close and remove underlying dc_context and callbacks. """

python/tests/test_account.py

@@ -2,6 +2,7 @@ from __future__ import print_function
 import pytest
 import os
 import queue
+import time
 from deltachat import const, Account
 from deltachat.message import Message
 from datetime import datetime, timedelta
@@ -641,18 +642,29 @@ class TestOnlineAccount:
         assert os.path.exists(msg_in.filename)
         assert os.stat(msg_in.filename).st_size == os.stat(path).st_size
 
-    def test_import_export_online_all(self, acfactory, tmpdir):
+    def test_import_export_online_all(self, acfactory, tmpdir, lp):
         ac1 = acfactory.get_online_configuring_account()
         wait_configuration_progress(ac1, 1000)
 
+        lp.sec("create some chat content")
         contact1 = ac1.create_contact("some1@hello.com", name="some1")
         chat = ac1.create_chat_by_contact(contact1)
         chat.send_text("msg1")
         backupdir = tmpdir.mkdir("backup")
+
+        lp.sec("export all to {}".format(backupdir))
         path = ac1.export_all(backupdir.strpath)
         assert os.path.exists(path)
+        t = time.time()
 
+        lp.sec("get fresh empty account")
         ac2 = acfactory.get_unconfigured_account()
+
+        lp.sec("get latest backup file")
+        path2 = ac2.get_latest_backupfile(backupdir.strpath)
+        assert path2 == path
+
+        lp.sec("import backup and check it's proper")
         ac2.import_all(path)
         contacts = ac2.get_contacts(query="some1")
         assert len(contacts) == 1
@@ -663,6 +675,18 @@ class TestOnlineAccount:
         assert len(messages) == 1
         assert messages[0].text == "msg1"
 
+        pytest.xfail("cannot export twice yet, probably due to interrupt_idle failing")
+        # wait until a second passed since last backup
+        # because get_latest_backupfile() shall return the latest backup
+        # from a UI it's unlikely anyone manages to export two
+        # backups in one second.
+        time.sleep(max(0, 1 - (time.time() - t)))
+        lp.sec("Second-time export all to {}".format(backupdir))
+        path2 = ac1.export_all(backupdir.strpath)
+        assert os.path.exists(path2)
+        assert path2 != path
+        assert ac2.get_latest_backupfile(backupdir.strpath) == path2
+
     def test_ac_setup_message(self, acfactory, lp):
         # note that the receiving account needs to be configured and running
         # before ther setup message is send. DC does not read old messages