diff --git a/plinth/modules/mumble/tests/test_functional.py b/plinth/modules/mumble/tests/test_functional.py
index 4a9912f2e..83cd6ef91 100644
--- a/plinth/modules/mumble/tests/test_functional.py
+++ b/plinth/modules/mumble/tests/test_functional.py
@@ -18,15 +18,38 @@ class TestMumbleApp(functional.BaseAppTests):
     # TODO: Requires a valid domain with certificates to complete setup.
     check_diagnostics = False
 
-    # TODO: Improve test_backup_restore to actually check that data such
-    # as rooms, identity or certificates are restored.
+    @staticmethod
+    def test_change_root_channel_name(session_browser):
+        """Test changing root channel name."""
+        functional.set_app_form_value(session_browser, 'mumble',
+                                      'id_root_channel_name', 'test-channel')
+        assert session_browser.find_by_id(
+            'id_root_channel_name').value == 'test-channel'
 
-    def test_change_root_channel_name(self, session_browser):
-        functional.app_enable(session_browser, 'mumble')
-        functional.nav_to_module(session_browser, 'mumble')
-        session_browser.find_by_id('id_root_channel_name').fill('testing123')
-        functional.submit(session_browser, form_class='form-configuration')
+    @staticmethod
+    def test_set_super_user_password(session_browser):
+        """Test setting the super user password."""
+        functional.set_app_form_value(session_browser, 'mumble',
+                                      'id_super_user_password', 'testsu123')
 
+    @staticmethod
+    def test_set_join_password(session_browser):
+        """Test setting join password."""
+        functional.set_app_form_value(session_browser, 'mumble',
+                                      'id_join_password', 'testjoin123')
+
+    @pytest.mark.backups
+    def test_backup_restore(self, session_browser):
+        """Test that backup and restore operations work on the app."""
+        functional.set_app_form_value(session_browser, 'mumble',
+                                      'id_root_channel_name', 'pre-backup')
+        functional.backup_create(session_browser, self.app_name,
+                                 'test_' + self.app_name)
+        functional.set_app_form_value(session_browser, 'mumble',
+                                      'id_root_channel_name', 'post-backup')
+        functional.backup_restore(session_browser, self.app_name,
+                                  'test_' + self.app_name)
         functional.nav_to_module(session_browser, 'mumble')
         assert session_browser.find_by_id(
-            'id_root_channel_name').value == 'testing123'
+            'id_root_channel_name').value == 'pre-backup'
+        self.assert_app_running(session_browser)
diff --git a/plinth/tests/functional/__init__.py b/plinth/tests/functional/__init__.py
index 651df6081..07eebec29 100644
--- a/plinth/tests/functional/__init__.py
+++ b/plinth/tests/functional/__init__.py
@@ -203,6 +203,17 @@ def submit(browser, element=None, form_class=None, expected_url=None):
             browser.find_by_css('input[type=submit]').click()
 
 
+def set_app_form_value(browser, app_id, element_id, value):
+    """Change a value in the form and submit."""
+    nav_to_module(browser, app_id)
+    original_url = browser.url
+    browser.find_by_id(element_id).fill(value)
+    submit(browser, form_class='form-configuration')
+    # Check that there are no errors
+    assert browser.url == original_url
+    assert not browser.find_by_css('.alert-danger')
+
+
 def change_checkbox_status(browser, app_name, checkbox_id,
                            change_status_to='enabled'):
     """Change checkbox status."""