change error code to 400

Author: ngxson

tools/server/server.cpp

@@ -1227,7 +1227,7 @@ static json format_error_response(const std::string & message, const enum error_
             break;
         case ERROR_TYPE_EXCEED_CONTEXT_SIZE:
             type_str = "exceed_context_size_error";
-            code = 500;
+            code = 400;
             break;
     }
     return json {

tools/server/tests/unit/test_chat_completion.py

@@ -395,7 +395,7 @@ def test_context_size_exceeded():
             {"role": "user", "content": "What is the best book"},
         ] * 100, # make the prompt too long
     })
-    assert res.status_code == 500
+    assert res.status_code == 400
     assert "error" in res.body
     assert res.body["error"]["type"] == "exceed_context_size_error"
     assert res.body["error"]["n_prompt_tokens"] > 0