test: verify real kbqa workflow

backend/tests/unit/test_sse.py

@@ -0,0 +1,8 @@
+from kbqa.chat.sse import encode_event, encode_ping
+
+
+def test_sse_encodes_single_line_utf8_json() -> None:
+    assert encode_event("token", {"content": "知识"}) == (
+        'event: token\ndata: {"content":"知识"}\n\n'.encode()
+    )
+    assert encode_ping() == b": ping\n\n"