ai-agent-book/chapter2/kv-cache/tests/test_error_handling.py

#!/usr/bin/env python3
"""Offline regressions for local tool error handling."""

from agent import LocalFileTools

def test_error_handling():
    """Test that local tools return structured errors instead of raising."""

    print("🧪 Testing Error Handling in Tool Execution")
    print("="*60)

    # Test local tools directly first
    print("\n1️⃣ Testing direct tool error handling:")
    tools = LocalFileTools(root_dir="../..")

    # Test with invalid arguments
    print("   Testing read_file with extra 'limit' parameter...")
    # The tool should ignore the extra parameter
    result = tools.read_file("chapter1/context/README.md")
    print(f"   Result: {'✓ Success' if result.get('success') else '✗ Error'}")
    assert result.get("success") is True

    # Test with non-existent file
    print("   Testing read_file with non-existent file...")
    result = tools.read_file("non_existent_file.txt")
    print(f"   Result: {'✓ Error handled' if not result.get('success') else '✗ Unexpected success'}")
    print(f"   Error message: {result.get('error', 'N/A')}")
    assert result.get("success") is False
    assert "File not found" in result.get("error", "")

    # Test security boundary
    print("   Testing security boundary...")
    result = tools.read_file("../../../../etc/passwd")
    print(f"   Result: {'✓ Access denied' if 'Access denied' in result.get('error', '') else '✗ Security issue'}")
    assert result.get("success") is False
    assert "Access denied" in result.get("error", "")

    print("\n" + "="*60)
    print("✅ Error handling test complete!")
    print("\nKey findings:")
    print("  • Tools return errors as results instead of throwing exceptions")
    print("  • Unexpected arguments are filtered out safely")
    print("  • Security boundaries are enforced")

if __name__ == "__main__":
    test_error_handling()