test(minimax): add client instantiation unit tests to catch credential and base URL regressions

tests/test_minimax_provider.py

@@ -1,5 +1,6 @@
 import unittest.mock
 from unittest.mock import patch, MagicMock
+import pytest
 from src import ai_client
 
 def test_minimax_model_selection() -> None:
@@ -62,3 +63,28 @@ def test_minimax_reasoning_extractor_omitted_when_caps_reasoning_false() -> None
       patch("src.ai_client._get_deepseek_tools", return_value=[]):
   ai_client._send_minimax("system", "user", ".", None, "", False, None, None, None)
  assert len(captured_kwargs) >= 1
+
+def test_minimax_ensure_client_instantiation() -> None:
+ """Verify that _ensure_minimax_client instantiates the OpenAI client with correct credentials and base URL."""
+ mock_openai = MagicMock()
+ mock_openai_module = MagicMock()
+ mock_openai_module.OpenAI = mock_openai
+ 
+ with patch("src.ai_client._require_warmed", return_value=mock_openai_module), \
+      patch("src.ai_client._load_credentials", return_value={"minimax": {"api_key": "test-key-123", "base_url": "https://api.minimax.io/v1"}}):
+  # Reset client state to force instantiation
+  ai_client._minimax_client = None
+  ai_client._ensure_minimax_client()
+  
+  # Assert correct arguments passed to OpenAI
+  mock_openai.assert_called_once_with(api_key="test-key-123", base_url="https://api.minimax.io/v1")
+  assert ai_client._minimax_client == mock_openai.return_value
+
+def test_minimax_ensure_client_missing_key_raises_value_error() -> None:
+ """Verify that _ensure_minimax_client raises ValueError if API key is missing."""
+ mock_openai_module = MagicMock()
+ with patch("src.ai_client._require_warmed", return_value=mock_openai_module), \
+      patch("src.ai_client._load_credentials", return_value={}):
+  ai_client._minimax_client = None
+  with pytest.raises(ValueError, match="MiniMax API key not found in credentials.toml"):
+   ai_client._ensure_minimax_client()