"""Test utility helpers for collection handling."""

from typing import Iterable, TypeVar

T = TypeVar('T')


def dedupe(items: Iterable[T]) -> list[T]:
    """Remove duplicates while preserving order."""
    seen: set[T] = set()
    uniq: list[T] = []
    for value in items:
        if value and value not in seen:
            seen.add(value)
            uniq.append(value)
    return uniq