test(mistral): cover content-part flattening, get_models errors, and cost dispatch

Codecov flagged 16 uncovered lines across the PR. Each gap was a real
untested behavior rather than dead code, so this covers them with meaningful
assertions instead of coverage filler: OpenAI content-part message lists must
flatten to their text with non-text and malformed parts dropped, an assistant
turn with content=None plus tool_calls (the OpenAI SDK shape) must map to a
function.call entry without emitting an empty message entry, a message.output
with null content must transform gracefully, get_models must raise cleanly
without credentials and on non-2xx responses, the shared
get_cost_for_web_search_request dispatcher must route provider mistral to the
new cost calculator, and non-dict tool entries in a request body must not
crash allowlist extraction or shadow real tools that need checking. The two
mistral files codecov called out are now at 100% line coverage locally

tests/test_litellm/llms/mistral/conversations/test_mistral_conversations_transformation.py

@@ -213,6 +213,60 @@ def test_transform_request_maps_random_seed():
     assert body["completion_args"] == {"random_seed": 7}
 
 
+def test_transform_request_flattens_content_part_lists():
+    """OpenAI content-parts messages must flatten to their text; non-text parts
+    and malformed entries are dropped, not crashed on."""
+    cfg = MistralConversationsConfig()
+    body = cfg.transform_request(
+        model="mistral-medium-latest",
+        messages=[
+            {"role": "system", "content": [{"type": "text", "text": "Be brief."}]},
+            {
+                "role": "user",
+                "content": [
+                    {"type": "text", "text": "What is "},
+                    {"type": "image_url", "image_url": {"url": "https://example.com/x.png"}},
+                    "not-a-dict",
+                    {"type": "text", "text": "the weather?"},
+                ],
+            },
+        ],
+        optional_params={"web_search_options": {}},
+        litellm_params={},
+        headers={},
+    )
+    assert body["instructions"] == "Be brief."
+    assert body["inputs"] == [{"role": "user", "content": "What is the weather?"}]
+
+
+def test_transform_request_assistant_null_content_with_tool_calls():
+    """The OpenAI SDK emits assistant tool-call turns with content=None; that must
+    map to a function.call entry with no empty assistant message entry."""
+    cfg = MistralConversationsConfig()
+    body = cfg.transform_request(
+        model="mistral-medium-latest",
+        messages=[
+            {"role": "user", "content": "weather?"},
+            {
+                "role": "assistant",
+                "content": None,
+                "tool_calls": [
+                    {"id": "call_1", "type": "function", "function": {"name": "get_weather", "arguments": "{}"}}
+                ],
+            },
+            {"role": "tool", "tool_call_id": "call_1", "content": "18C"},
+        ],
+        optional_params={"web_search_options": {}},
+        litellm_params={},
+        headers={},
+    )
+    assert body["inputs"] == [
+        {"role": "user", "content": "weather?"},
+        {"type": "function.call", "tool_call_id": "call_1", "name": "get_weather", "arguments": "{}"},
+        {"type": "function.result", "tool_call_id": "call_1", "result": "18C"},
+    ]
+
+
 def test_get_complete_url():
     cfg = MistralConversationsConfig()
     assert (
@@ -347,6 +401,18 @@ def test_transform_response_without_message_output_is_graceful():
     assert mr.choices[0].message.content is None
 
 
+def test_transform_response_null_message_content_is_graceful():
+    mr = _transform(
+        {
+            "conversation_id": "conv_1",
+            "outputs": [{"type": "message.output", "role": "assistant", "content": None}],
+            "usage": {"prompt_tokens": 1, "completion_tokens": 0, "total_tokens": 1},
+        }
+    )
+    assert mr.choices[0].message.content is None
+    assert getattr(mr.choices[0].message, "annotations", None) is None
+
+
 @pytest.mark.parametrize(
     "web_search_kwargs",
     [

tests/test_litellm/llms/mistral/test_mistral_common_utils.py

@@ -79,3 +79,14 @@ class TestMistralModelInfo:
             "mistral/mistral-medium-latest",
             "mistral/mistral-large-latest",
         ]
+
+    def test_get_models_raises_without_api_key(self, monkeypatch):
+        monkeypatch.delenv("MISTRAL_API_KEY", raising=False)
+        with pytest.raises(ValueError, match="MISTRAL_API_BASE or MISTRAL_API_KEY"):
+            MistralModelInfo().get_models()
+
+    def test_get_models_raises_on_http_error(self, respx_mock):
+        litellm.disable_aiohttp_transport = True
+        respx_mock.get("https://api.mistral.ai/v1/models").respond(status_code=500, text="boom")
+        with pytest.raises(Exception, match="Status code: 500"):
+            MistralModelInfo().get_models()

tests/test_litellm/llms/mistral/test_mistral_cost_calculator.py

@@ -36,6 +36,21 @@ def test_cost_per_web_search_request_no_details_is_zero():
     assert cost_per_web_search_request(usage=usage, model_info=model_info) == 0.0
 
 
+def test_get_cost_for_web_search_request_dispatches_for_mistral():
+    """The shared dispatcher must route provider 'mistral' to this cost calculator;
+    without the mistral branch the surcharge silently becomes None."""
+    from litellm.llms import get_cost_for_web_search_request
+
+    usage = Usage(
+        prompt_tokens=10,
+        completion_tokens=5,
+        total_tokens=15,
+        prompt_tokens_details=PromptTokensDetailsWrapper(web_search_requests=2),
+    )
+    model_info = litellm.get_model_info("mistral/mistral-medium-latest")
+    assert get_cost_for_web_search_request("mistral", usage=usage, model_info=model_info) == pytest.approx(0.06)
+
+
 def _conversation_response(connectors: dict = None, execution_names: list = None) -> ModelResponse:
     """Build a transformed ModelResponse from a Conversations payload.
 

tests/test_litellm/proxy/test_tools_allowlist_enforcement.py

@@ -260,6 +260,22 @@ class TestCheckToolsAllowlist:
         assert exc_info.value.type == ProxyErrorTypes.tool_access_denied
         assert "web_search" in str(exc_info.value.message)
 
+    @pytest.mark.asyncio
+    async def test_non_dict_tool_entries_skipped_without_masking_real_tools(self):
+        """Malformed tool entries must not crash extraction or shadow the real
+        tools that still need allowlist checking."""
+        token = _token(metadata={"allowed_tools": ["get_weather"]})
+        body = {"tools": ["junk", 42, {"type": "web_search"}]}
+        with pytest.raises(ProxyException) as exc_info:
+            await check_tools_allowlist(
+                request_body=body,
+                valid_token=token,
+                team_object=None,
+                route="/v1/chat/completions",
+            )
+        assert exc_info.value.type == ProxyErrorTypes.tool_access_denied
+        assert "web_search" in str(exc_info.value.message)
+
     @pytest.mark.asyncio
     async def test_builtin_web_search_allowed_when_listed(self):
         token = _token(metadata={"allowed_tools": ["web_search"]})