mgmt: add mgmt.label.Index method

QubesOS/qubes-issues#2622

qubes/mgmt.py

@@ -464,6 +464,20 @@ class QubesMgmt(AbstractQubesMgmt):
 
         return label.color
 
+    @api('mgmt.label.Index', no_payload=True)
+    @asyncio.coroutine
+    def label_index(self):
+        assert self.dest.name == 'dom0'
+
+        try:
+            label = self.app.get_label(self.arg)
+        except KeyError:
+            raise qubes.exc.QubesValueError
+
+        self.fire_event_for_permission(label=label)
+
+        return str(label.index)
+
     @api('mgmt.label.Create')
     @asyncio.coroutine
     def label_create(self, untrusted_payload):

qubes/tests/mgmt.py

@@ -681,6 +681,15 @@ class TC_00_VMs(MgmtTestCase):
             [unittest.mock.call('red')])
         self.assertFalse(self.app.save.called)
 
+    def test_195_label_index(self):
+        self.app.get_label = unittest.mock.Mock()
+        self.app.get_label.configure_mock(**{'return_value.index': 1})
+        value = self.call_mgmt_func(b'mgmt.label.Index', b'dom0', b'red')
+        self.assertEqual(value, '1')
+        self.assertEqual(self.app.get_label.mock_calls,
+            [unittest.mock.call('red')])
+        self.assertFalse(self.app.save.called)
+
     def test_200_label_create(self):
         self.app.get_label = unittest.mock.Mock()
         self.app.get_label.side_effect=KeyError