import ast
from pathlib import Path


MODULE = Path(__file__).parents[1] / "netbox_site_prefix" / "tables.py"


def _load_first_word():
    """Load the pure helper without requiring a local NetBox installation."""
    module = ast.parse(MODULE.read_text(encoding="utf-8"))
    function = next(
        node for node in module.body
        if isinstance(node, ast.FunctionDef) and node.name == "first_word"
    )
    namespace = {}
    exec(compile(ast.Module(body=[function], type_ignores=[]), str(MODULE), "exec"), namespace)
    return namespace["first_word"]


def test_first_word():
    first_word = _load_first_word()

    assert first_word("Berlin Campus West") == "Berlin"
    assert first_word("  DC01\tFrankfurt ") == "DC01"


def test_first_word_handles_missing_or_blank_value():
    first_word = _load_first_word()

    assert first_word(None) is None
    assert first_word("   ") is None