[Model] Add mistral function calling format to all models loaded with "mistral" format (#8515)

Co-authored-by: Cyrus Leung <cyrus.tl.leung@gmail.com>

tests/models/decoder_only/language/test_mistral.py

@@ -4,13 +4,61 @@ Run `pytest tests/models/test_mistral.py`.
 """
 import pytest
 
+from vllm import SamplingParams
+
 from ...utils import check_logprobs_close
 
 MODELS = [
     "mistralai/Mistral-7B-Instruct-v0.1",
     "mistralai/Mistral-7B-Instruct-v0.3",
+    # Mistral-Nemo is to big for CI, but passes locally
+    # "mistralai/Mistral-Nemo-Instruct-2407"
 ]
 
+SAMPLING_PARAMS = SamplingParams(max_tokens=512, temperature=0.0, logprobs=5)
+
+# for function calling
+TOOLS = [{
+    "type": "function",
+    "function": {
+        "name": "get_current_weather",
+        "description": "Get the current weather in a given location",
+        "parameters": {
+            "type": "object",
+            "properties": {
+                "city": {
+                    "type":
+                    "string",
+                    "description":
+                    "The city to find the weather for, e.g. 'San Francisco'"
+                },
+                "state": {
+                    "type":
+                    "string",
+                    "description":
+                    "the two-letter abbreviation for the state that the city is"
+                    " in, e.g. 'CA' which would mean 'California'"
+                },
+                "unit": {
+                    "type": "string",
+                    "description": "The unit to fetch the temperature in",
+                    "enum": ["celsius", "fahrenheit"]
+                }
+            },
+            "required": ["city", "state", "unit"]
+        }
+    }
+}]
+MSGS = [{
+    "role":
+    "user",
+    "content": ("Can you tell me what the temperate"
+                " will be in Dallas, in fahrenheit?")
+}]
+EXPECTED_FUNC_CALL = (
+    '[{"name": "get_current_weather", "arguments": '
+    '{"city": "Dallas", "state": "TX", "unit": "fahrenheit"}}]')
+
 
 @pytest.mark.parametrize("model", MODELS)
 @pytest.mark.parametrize("dtype", ["bfloat16"])
@@ -81,3 +129,22 @@ def test_mistral_format(
         name_0="hf",
         name_1="mistral",
     )
+
+
+@pytest.mark.parametrize("dtype", ["bfloat16"])
+@pytest.mark.parametrize("model", MODELS[1:])  # v1 can't do func calling
+def test_mistral_function_calling(
+    vllm_runner,
+    model: str,
+    dtype: str,
+) -> None:
+    with vllm_runner(model,
+                     dtype=dtype,
+                     tokenizer_mode="mistral",
+                     config_format="mistral",
+                     load_format="mistral") as vllm_model:
+        outputs = vllm_model.model.chat(MSGS,
+                                        tools=TOOLS,
+                                        sampling_params=SAMPLING_PARAMS)
+
+        assert outputs[0].outputs[0].text.strip() == EXPECTED_FUNC_CALL