test: lazy-load LLM provider clients and add API-key fixtures so the test suite runs cleanly without credentials (#588)

tests/conftest.py

@@ -0,0 +1,42 @@
+"""Shared pytest fixtures that prevent CI hangs when API keys are absent."""
+
+import os
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+
+def pytest_configure(config):
+    for marker in ("unit", "integration", "smoke"):
+        config.addinivalue_line("markers", f"{marker}: {marker}-level tests")
+
+
+_API_KEY_ENV_VARS = (
+    "OPENAI_API_KEY",
+    "GOOGLE_API_KEY",
+    "ANTHROPIC_API_KEY",
+    "XAI_API_KEY",
+    "DEEPSEEK_API_KEY",
+    "DASHSCOPE_API_KEY",
+    "ZHIPU_API_KEY",
+    "OPENROUTER_API_KEY",
+    "AZURE_OPENAI_API_KEY",
+    "ALPHA_VANTAGE_API_KEY",
+)
+
+
+@pytest.fixture(autouse=True)
+def _dummy_api_keys(monkeypatch):
+    for env_var in _API_KEY_ENV_VARS:
+        monkeypatch.setenv(env_var, os.environ.get(env_var, "placeholder"))
+
+
+@pytest.fixture()
+def mock_llm_client():
+    client = MagicMock()
+    client.get_llm.return_value = MagicMock()
+    with patch(
+        "tradingagents.llm_clients.factory.create_llm_client",
+        return_value=client,
+    ):
+        yield client