[Bugfix] Support missing tool parameters in mistral tokenizer (#12884)

Signed-off-by: Florian Greinacher <florian.greinacher@siemens.com>

tests/tokenization/test_mistral_tokenizer.py

@@ -0,0 +1,50 @@
+# SPDX-License-Identifier: Apache-2.0
+
+import pytest
+from mistral_common.protocol.instruct.messages import UserMessage
+from mistral_common.protocol.instruct.request import ChatCompletionRequest
+from mistral_common.protocol.instruct.tool_calls import Function, Tool
+
+from vllm.transformers_utils.tokenizers.mistral import (
+    make_mistral_chat_completion_request)
+
+
+# yapf: enable
+@pytest.mark.parametrize(
+    "openai_request,expected_mistral_request",
+    [(
+        {
+            "messages": [{
+                "role": "user",
+                "content": "What is the current local date and time?",
+            }],
+            "tools": [{
+                "type": "function",
+                "function": {
+                    "description": "Fetch the current local date and time.",
+                    "name": "get_current_time",
+                },
+            }],
+        },
+        ChatCompletionRequest(
+            messages=[
+                UserMessage(content="What is the current local date and time?")
+            ],
+            tools=[
+                Tool(
+                    type="function",
+                    function=Function(
+                        name="get_current_time",
+                        description="Fetch the current local date and time.",
+                        parameters={},
+                    ),
+                )
+            ],
+        ),
+    )],
+)
+def test_make_mistral_chat_completion_request(openai_request,
+                                              expected_mistral_request):
+    assert (make_mistral_chat_completion_request(
+        openai_request["messages"],
+        openai_request["tools"]) == expected_mistral_request)