backups: Fix iteration over loaded modules

Add tests for affected functions.

Signed-off-by: James Valleroy <jvalleroy@mailbox.org>
Reviewed-by: Joseph Nuthalapati <njoseph@thoughtworks.com>

plinth/modules/backups/backups.py

@@ -180,7 +180,7 @@ def restore_apps(restore_handler, app_names=None, create_subvolume=True):
 def _list_of_all_apps_for_backup():
     """Return a list of all applications that can be backed up."""
     apps = []
-    for module_name, module in module_loader.loaded_modules.values():
+    for module_name, module in module_loader.loaded_modules.items():
         # Not installed
         if module.setup_helper.get_state() == 'needs-setup':
             continue
@@ -197,7 +197,7 @@ def _list_of_all_apps_for_backup():
 def _get_apps_in_order(app_names):
     """Return a list of app modules in order of dependency."""
     apps = []
-    for module_name, module in module_loader.loaded_modules.values():
+    for module_name, module in module_loader.loaded_modules.items():
         if module_name in app_names:
             apps.append((module_name, module))
 

plinth/modules/backups/tests/test_backups.py

@@ -0,0 +1,46 @@
+#
+# This file is part of FreedomBox.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+"""
+Tests for backups module.
+"""
+
+import unittest
+
+from plinth.module_loader import load_modules
+from ..backups import _list_of_all_apps_for_backup, _get_apps_in_order
+
+
+class TestBackups(unittest.TestCase):
+    """Test cases for backups module."""
+
+    def test__list_of_all_apps_for_backups(self):
+        """Test that apps supporting backup are included in returned list."""
+        load_modules()
+        apps = _list_of_all_apps_for_backup()
+        assert isinstance(apps, list)
+        # apps may be empty, if no apps supporting backup are installed.
+
+    def test__get_apps_in_order(self):
+        """Test that apps are listed in correct dependency order."""
+        load_modules()
+        app_names = ['config', 'names']
+        apps = _get_apps_in_order(app_names)
+        ordered_app_names = [x[0] for x in apps]
+
+        names_index = ordered_app_names.index('names')
+        config_index = ordered_app_names.index('config')
+        assert names_index < config_index