Agent Testing and Reliability

Testing Agent Reliability

import pytest
from unittest.mock import patch, MagicMock

# Test agent tool selection
def test_agent_uses_search_for_current_events():
    with patch("tools.search_web") as mock_search:
        mock_search.return_value = "Python 3.13 released Oct 2024"
        result = agent.invoke({"input": "What are Python 3.13 features?"})
        mock_search.assert_called_once()
        assert "3.13" in result["output"]

# Test agent handles tool failure gracefully
def test_agent_handles_tool_error():
    with patch("tools.search_web", side_effect=Exception("API timeout")):
        result = agent.invoke({"input": "Search for news"})
        # Agent should acknowledge failure, not crash
        assert "error" in result["output"].lower() or "unable" in result["output"].lower()

# Test agent respects max iterations
def test_agent_does_not_loop_forever():
    agent_with_limit = build_agent(max_iterations=5)
    result = agent_with_limit.invoke({"input": "Impossible task"})
    assert result is not None  # did not hang

# Integration test with real LLM (expensive, run rarely)
@pytest.mark.integration
def test_full_agent_task():
    result = agent.invoke({"input": "Calculate 15% of 847"})
    assert "127.05" in result["output"]