jsxc: Enable backup/restore (no data)

Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

functional_tests/features/jsxc.feature

@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
-@apps @jsxc
+@apps @jsxc @backups
 Feature: JSXC XMPP Client
   Run the JSXC XMPP client.
 
@@ -25,3 +25,10 @@ Background:
 Scenario: Install jsxc application
   Given the jsxc application is installed
   Then the jsxc site should be available
+
+Scenario: Backup and restore jsxc
+  Given the jsxc application is installed
+  When I create a backup of the jsxc app data
+  And I export the jsxc app data backup
+  And I restore the jsxc app data backup
+  Then the jsxc site should be available

plinth/modules/jsxc/__init__.py

@@ -18,16 +18,17 @@
 FreedomBox app to configure XMPP web client/jsxc.
 """
 
-from django.urls import reverse_lazy
-from django.utils.translation import ugettext_lazy as _
 import logging
 import socket
 
+from django.urls import reverse_lazy
+from django.utils.translation import ugettext_lazy as _
+
 from plinth import frontpage
 from plinth import service as service_module
 from plinth.menu import main_menu
-from .manifest import clients
 
+from .manifest import backup, clients
 
 version = 1
 
@@ -38,7 +39,6 @@ name = _('JSXC')
 short_description = _('Chat Client')
 
 description = [
-
     _('JSXC is a web client for XMPP. Typically it is used with an XMPP '
       'server running locally.'),
 ]
@@ -81,8 +81,7 @@ def setup(helper, old_version=None):
 def add_shortcut():
     frontpage.add_shortcut('jsxc', name=name,
                            short_description=short_description,
-                           url=reverse_lazy('jsxc:jsxc'),
-                           login_required=True)
+                           url=reverse_lazy('jsxc:jsxc'), login_required=True)
 
 
 def is_enabled():

plinth/modules/jsxc/manifest.py

@@ -19,6 +19,7 @@ from django.urls import reverse_lazy
 from django.utils.translation import ugettext_lazy as _
 
 from plinth.clients import validate
+from plinth.modules.backups.api import validate as validate_backup
 
 clients = validate([{
     'name': _('JSXC'),
@@ -27,3 +28,5 @@ clients = validate([{
         'url': reverse_lazy('jsxc:jsxc')
     }]
 }])
+
+backup = validate_backup({})