test: trim redundant MCP gateway tests

- Drop test_initial_call_success_does_not_emit_error_event: the tool-call
  happy path (test_tool_call_happy_path_emits_no_error_event) already guards
  against false-positive error events and exercises more of the changed code
  (tool-exec + follow-up success paths).
- Drop the stream=True parametrization on the zero-resolved-tools guard: the
  guard runs before the stream/non-stream branch in aresponses_api_with_mcp,
  so both cases hit identical code.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/test_litellm/responses/mcp/test_mcp_empty_resolved_tools.py

@@ -40,8 +40,9 @@ def _model_response() -> ResponsesAPIResponse:
 
 
 @pytest.mark.asyncio
-@pytest.mark.parametrize("stream", [False, True])
-async def test_zero_resolved_mcp_tools_raises_before_model_call(monkeypatch, stream):
+async def test_zero_resolved_mcp_tools_raises_before_model_call(monkeypatch):
+    # The guard runs before the stream/non-stream branch in
+    # aresponses_api_with_mcp, so one case covers both.
     _patch_resolved_tools(monkeypatch, [])
     aresponses_mock = AsyncMock()
     monkeypatch.setattr(responses_main_module, "aresponses", aresponses_mock)
@@ -50,7 +51,7 @@ async def test_zero_resolved_mcp_tools_raises_before_model_call(monkeypatch, str
         await responses_main_module.aresponses_api_with_mcp(
             input="how many links do i have?",
             model="gpt-4",
-            stream=stream,
+            stream=False,
             tools=[MCP_TOOL],
         )
 

tests/test_litellm/responses/mcp/test_mcp_streaming_iterator.py

@@ -130,24 +130,6 @@ async def test_eager_creation_reraises_pre_stream_failure_as_http_error(monkeypa
     assert "resp_bogus" in str(excinfo.value)
 
 
-@pytest.mark.asyncio
-async def test_initial_call_success_does_not_emit_error_event(monkeypatch):
-    """Happy path is unchanged: no error event, stream flows as before."""
-    monkeypatch.setattr(
-        responses_main_module,
-        "aresponses",
-        AsyncMock(return_value=_text_only_stream("all good")),
-    )
-
-    iterator = _make_lazy_iterator()
-    chunks = [chunk async for chunk in iterator]
-
-    assert all(getattr(c, "type", None) != ResponsesAPIStreamEvents.ERROR for c in chunks)
-    completed = [c for c in chunks if getattr(c, "type", None) == ResponsesAPIStreamEvents.RESPONSE_COMPLETED]
-    assert len(completed) == 1
-    assert iterator._initial_creation_error is None
-
-
 import types
 from unittest.mock import MagicMock