feat(subscribe): add modified event payload contract (#6012)

tests/test_subscribe_modified_event.py

@@ -0,0 +1,50 @@
+from app.schemas.event import SubscribeModifiedEventData
+
+
+def test_subscribe_modified_event_data_computes_sorted_fields():
+    data = SubscribeModifiedEventData(
+        subscribe_id=7,
+        old_subscribe_info={"state": "R", "lack_episode": 3, "name": "A"},
+        subscribe_info={"state": "S", "lack_episode": 3, "name": "B"},
+        scene="status",
+    )
+
+    assert data.fields == ["name", "state"]
+    assert data.to_dict() == {
+        "subscribe_id": 7,
+        "old_subscribe_info": {"state": "R", "lack_episode": 3, "name": "A"},
+        "subscribe_info": {"state": "S", "lack_episode": 3, "name": "B"},
+        "scene": "status",
+        "fields": ["name", "state"],
+    }
+
+
+def test_subscribe_modified_event_data_diffs_missing_keys_as_none():
+    data = SubscribeModifiedEventData(
+        subscribe_id=8,
+        old_subscribe_info={"state": "R", "episode_priority": {"1": 80}},
+        subscribe_info={"state": "R"},
+        scene="reset",
+    )
+
+    assert data.fields == ["episode_priority"]
+    assert set(data.to_dict()) == {
+        "subscribe_id",
+        "old_subscribe_info",
+        "subscribe_info",
+        "scene",
+        "fields",
+    }
+
+
+def test_subscribe_modified_event_data_ignores_caller_supplied_fields():
+    data = SubscribeModifiedEventData(
+        subscribe_id=9,
+        old_subscribe_info={"state": "R"},
+        subscribe_info={"state": "S"},
+        scene="update",
+        fields=["fake"],
+    )
+
+    assert data.fields == ["state"]
+    assert data.to_dict()["fields"] == ["state"]