feat: openai_api_compatible support config stream_mode_delimiter (#2190)

Co-authored-by: wanggang <wanggy01@servyou.com.cn>
Co-authored-by: Chenhe Gu <guchenhe@gmail.com>

api/tests/integration_tests/model_runtime/openai_api_compatible/test_llm.py

@@ -12,6 +12,7 @@ from core.model_runtime.model_providers.openai_api_compatible.llm.llm import OAI
 Using Together.ai's OpenAI-compatible API as testing endpoint
 """
 
+
 def test_validate_credentials():
     model = OAIAPICompatLargeLanguageModel()
 
@@ -34,6 +35,7 @@ def test_validate_credentials():
         }
     )
 
+
 def test_invoke_model():
     model = OAIAPICompatLargeLanguageModel()
 
@@ -65,9 +67,47 @@ def test_invoke_model():
     assert isinstance(response, LLMResult)
     assert len(response.message.content) > 0
 
+
 def test_invoke_stream_model():
     model = OAIAPICompatLargeLanguageModel()
 
+    response = model.invoke(
+        model='mistralai/Mixtral-8x7B-Instruct-v0.1',
+        credentials={
+            'api_key': os.environ.get('TOGETHER_API_KEY'),
+            'endpoint_url': 'https://api.together.xyz/v1/',
+            'mode': 'chat',
+            'stream_mode_delimiter': '\\n\\n'
+        },
+        prompt_messages=[
+            SystemPromptMessage(
+                content='You are a helpful AI assistant.',
+            ),
+            UserPromptMessage(
+                content='Who are you?'
+            )
+        ],
+        model_parameters={
+            'temperature': 1.0,
+            'top_k': 2,
+            'top_p': 0.5,
+        },
+        stop=['How'],
+        stream=True,
+        user="abc-123"
+    )
+
+    assert isinstance(response, Generator)
+
+    for chunk in response:
+        assert isinstance(chunk, LLMResultChunk)
+        assert isinstance(chunk.delta, LLMResultChunkDelta)
+        assert isinstance(chunk.delta.message, AssistantPromptMessage)
+
+
+def test_invoke_stream_model_without_delimiter():
+    model = OAIAPICompatLargeLanguageModel()
+
     response = model.invoke(
         model='mistralai/Mixtral-8x7B-Instruct-v0.1',
         credentials={
@@ -100,6 +140,7 @@ def test_invoke_stream_model():
         assert isinstance(chunk.delta, LLMResultChunkDelta)
         assert isinstance(chunk.delta.message, AssistantPromptMessage)
 
+
 # using OpenAI's ChatGPT-3.5 as testing endpoint
 def test_invoke_chat_model_with_tools():
     model = OAIAPICompatLargeLanguageModel()
@@ -126,22 +167,22 @@ def test_invoke_chat_model_with_tools():
                 parameters={
                     "type": "object",
                     "properties": {
-                      "location": {
-                        "type": "string",
-                        "description": "The city and state e.g. San Francisco, CA"
-                      },
-                      "unit": {
-                        "type": "string",
-                        "enum": [
-                          "celsius",
-                          "fahrenheit"
-                        ]
-                      }
+                        "location": {
+                            "type": "string",
+                            "description": "The city and state e.g. San Francisco, CA"
+                        },
+                        "unit": {
+                            "type": "string",
+                            "enum": [
+                                "celsius",
+                                "fahrenheit"
+                            ]
+                        }
                     },
                     "required": [
-                      "location"
+                        "location"
                     ]
-                  }
+                }
             ),
         ],
         model_parameters={
@@ -156,6 +197,7 @@ def test_invoke_chat_model_with_tools():
     assert isinstance(result.message, AssistantPromptMessage)
     assert len(result.message.tool_calls) > 0
 
+
 def test_get_num_tokens():
     model = OAIAPICompatLargeLanguageModel()