Test: Added test cases for Create Session With Chat Assistant HTTP API (#6902)

### What problem does this PR solve?

cover [create session with chat
assistant](https://ragflow.io/docs/dev/http_api_reference#create-session-with-chat-assistant)
endpoints

### Type of change

- [x] add test cases

sdk/python/test/test_http_api/test_session_management/test_create_session_with_chat_assistant.py

@@ -0,0 +1,114 @@
+#
+#  Copyright 2025 The InfiniFlow Authors. All Rights Reserved.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+from concurrent.futures import ThreadPoolExecutor
+
+import pytest
+from common import INVALID_API_TOKEN, SESSION_WITH_CHAT_NAME_LIMIT, create_session_with_chat_assistant, delete_chat_assistants, list_session_with_chat_assistants
+from libs.auth import RAGFlowHttpApiAuth
+
+
+class TestAuthorization:
+    @pytest.mark.parametrize(
+        "auth, expected_code, expected_message",
+        [
+            (None, 0, "`Authorization` can't be empty"),
+            (
+                RAGFlowHttpApiAuth(INVALID_API_TOKEN),
+                109,
+                "Authentication error: API key is invalid!",
+            ),
+        ],
+    )
+    def test_invalid_auth(self, auth, expected_code, expected_message):
+        res = create_session_with_chat_assistant(auth, "chat_assistant_id")
+        assert res["code"] == expected_code
+        assert res["message"] == expected_message
+
+
+@pytest.mark.usefixtures("clear_session_with_chat_assistants")
+class TestSessionWithChatAssistantCreate:
+    @pytest.mark.parametrize(
+        "payload, expected_code, expected_message",
+        [
+            ({"name": "valid_name"}, 0, ""),
+            pytest.param({"name": "a" * (SESSION_WITH_CHAT_NAME_LIMIT + 1)}, 102, "", marks=pytest.mark.skip(reason="issues/")),
+            pytest.param({"name": 1}, 100, "", marks=pytest.mark.skip(reason="issues/")),
+            ({"name": ""}, 102, "`name` can not be empty."),
+            ({"name": "duplicated_name"}, 0, ""),
+            ({"name": "case insensitive"}, 0, ""),
+        ],
+    )
+    def test_name(self, get_http_api_auth, add_chat_assistants, payload, expected_code, expected_message):
+        _, _, chat_assistant_ids = add_chat_assistants
+        if payload["name"] == "duplicated_name":
+            create_session_with_chat_assistant(get_http_api_auth, chat_assistant_ids[0], payload)
+        elif payload["name"] == "case insensitive":
+            create_session_with_chat_assistant(get_http_api_auth, chat_assistant_ids[0], {"name": payload["name"].upper()})
+
+        res = create_session_with_chat_assistant(get_http_api_auth, chat_assistant_ids[0], payload)
+        assert res["code"] == expected_code, res
+        if expected_code == 0:
+            assert res["data"]["name"] == payload["name"]
+            assert res["data"]["chat_id"] == chat_assistant_ids[0]
+        else:
+            assert res["message"] == expected_message
+
+    @pytest.mark.parametrize(
+        "chat_assistant_id, expected_code, expected_message",
+        [
+            ("", 100, "<MethodNotAllowed '405: Method Not Allowed'>"),
+            ("invalid_chat_assistant_id", 102, "You do not own the assistant."),
+        ],
+    )
+    def test_invalid_chat_assistant_id(self, get_http_api_auth, chat_assistant_id, expected_code, expected_message):
+        res = create_session_with_chat_assistant(get_http_api_auth, chat_assistant_id, {"name": "valid_name"})
+        assert res["code"] == expected_code
+        assert res["message"] == expected_message
+
+    @pytest.mark.slow
+    def test_concurrent_create_session(self, get_http_api_auth, add_chat_assistants):
+        chunk_num = 1000
+        _, _, chat_assistant_ids = add_chat_assistants
+        res = list_session_with_chat_assistants(get_http_api_auth, chat_assistant_ids[0])
+        if res["code"] != 0:
+            assert False, res
+        chunks_count = len(res["data"])
+
+        with ThreadPoolExecutor(max_workers=5) as executor:
+            futures = [
+                executor.submit(
+                    create_session_with_chat_assistant,
+                    get_http_api_auth,
+                    chat_assistant_ids[0],
+                    {"name": f"session with chat assistant test {i}"},
+                )
+                for i in range(chunk_num)
+            ]
+        responses = [f.result() for f in futures]
+        assert all(r["code"] == 0 for r in responses)
+        res = list_session_with_chat_assistants(get_http_api_auth, chat_assistant_ids[0], {"page_size": chunk_num})
+        if res["code"] != 0:
+            assert False, res
+        assert len(res["data"]) == chunks_count + chunk_num
+
+    def test_add_session_to_deleted_chat_assistant(self, get_http_api_auth, add_chat_assistants):
+        _, _, chat_assistant_ids = add_chat_assistants
+        res = delete_chat_assistants(get_http_api_auth, {"ids": [chat_assistant_ids[0]]})
+        assert res["code"] == 0
+        res = create_session_with_chat_assistant(get_http_api_auth, chat_assistant_ids[0], {"name": "valid_name"})
+        print(res)
+        assert res["code"] == 102
+        assert res["message"] == "You do not own the assistant."