feat: implement mvp with email-first login flow and langgraph architecture

tests/test_researcher.py

@@ -0,0 +1,34 @@
+import pytest
+from unittest.mock import MagicMock, patch
+from langchain_core.messages import AIMessage
+from langchain_openai import ChatOpenAI
+from ea_chatbot.graph.nodes.researcher import researcher_node
+
+@pytest.fixture
+def mock_llm():
+    with patch("ea_chatbot.graph.nodes.researcher.get_llm_model") as mock_get_llm:
+        mock_llm_instance = MagicMock(spec=ChatOpenAI)
+        mock_get_llm.return_value = mock_llm_instance
+        yield mock_llm_instance
+
+def test_researcher_node_success(mock_llm):
+    """Test that researcher_node invokes LLM with web_search tool and returns messages."""
+    state = {
+        "question": "What is the capital of France?",
+        "messages": []
+    }
+    
+    mock_llm_with_tools = MagicMock()
+    mock_llm.bind_tools.return_value = mock_llm_with_tools
+    mock_llm_with_tools.invoke.return_value = AIMessage(content="The capital of France is Paris.")
+    
+    result = researcher_node(state)
+    
+    assert mock_llm.bind_tools.called
+    # Check that it was called with web_search
+    args, kwargs = mock_llm.bind_tools.call_args
+    assert {"type": "web_search"} in args[0]
+    
+    assert mock_llm_with_tools.invoke.called
+    assert "messages" in result
+    assert result["messages"][0].content == "The capital of France is Paris."