test_trim_messages_token_counter_shortcut_invalid() — langchain Function Reference

Source Code

libs/core/tests/unit_tests/messages/test_utils.py lines 710–725

def test_trim_messages_token_counter_shortcut_invalid() -> None:
    """Test that invalid `token_counter` shortcut raises `ValueError`."""
    messages = [
        SystemMessage("This is a test message"),
        HumanMessage("Another test message"),
    ]

    # Test with invalid shortcut - intentionally passing invalid string to verify
    # runtime error handling for dynamically-constructed inputs
    with pytest.raises(ValueError, match="Invalid token_counter shortcut 'invalid'"):
        trim_messages(  # type: ignore[call-overload]
            messages,
            max_tokens=50,
            token_counter="invalid",
            strategy="last",
        )