test_messages: Add and modify test for message labels.

Tests the conditions for moved and edited label along wth
UI differences.
Fixes #1253

tests/ui_tools/test_messages.py

@@ -1082,18 +1082,52 @@ def test_main_view_compact_output(
         assert len(view_components) == 1
         assert isinstance(view_components[0], Padding)
 
-    def test_main_view_generates_EDITED_label(
-        self, mocker, messages_successful_response
+    @pytest.mark.parametrize(
+        [
+            "message_edited",
+            "message_moved",
+            "expected_left_padding",
+            "expected_label_text",
+        ],
+        [
+            case(True, False, 7, "EDITED", id="message_indexed_to_edited_messages"),
+            case(False, True, 6, "MOVED", id="message_indexed_to_moved_messages"),
+            case(
+                False,
+                False,
+                0,
+                "EDITED",
+                id="message_neither_index_to_edited_messages_or_moved_messages",
+            ),
+        ],
+    )
+    def test_main_view_generates_EDITED_or_MOVED_label(
+        self,
+        mocker,
+        messages_successful_response,
+        message_edited,
+        message_moved,
+        expected_left_padding,
+        expected_label_text,
     ):
         messages = messages_successful_response["messages"]
         for message in messages:
-            self.model.index["edited_messages"].add(message["id"])
+            msg_id = message["id"]
+            message_index = {
+                "edited_messages": {msg_id} if message_edited else set(),
+                "moved_messages": {msg_id} if message_moved else set(),
+            }
+            self.model.index = dict(
+                self.model.index,
+                edited_messages=message_index["edited_messages"],
+                moved_messages=message_index["moved_messages"],
+            )
             msg_box = MessageBox(message, self.model, message)
             view_components = msg_box.main_view()
 
             label = view_components[0].original_widget.contents[0]
-            assert label[0].text == "EDITED"
-            assert label[1][1] == 7
+            assert label[0].text == expected_label_text
+            assert label[1][1] == expected_left_padding
 
     @pytest.mark.parametrize(
         "to_vary_in_last_message, update_required",