bitwarden-server/test/Common/Helpers/TestCaseHelper.cs

namespace Bit.Test.Common.Helpers
{
    public static class TestCaseHelper
    {
        public static IEnumerable<IEnumerable<T>> GetCombinations<T>(params T[] items)
        {
            var count = Math.Pow(2, items.Length);
            for (var i = 0; i < count; i++)
            {
                var str = Convert.ToString(i, 2).PadLeft(items.Length, '0');
                List<T> combination = new();
                for (var j = 0; j < str.Length; j++)
                {
                    if (str[j] == '1')
                    {
                        combination.Add(items[j]);
                    }
                }
                yield return combination;
            }
        }

        public static IEnumerable<IEnumerable<object>> GetCombinationsOfMultipleLists(params IEnumerable<object>[] optionLists)
        {
            if (!optionLists.Any())
            {
                yield break;
            }

            foreach (var item in optionLists.First())
            {
                var itemArray = new[] { item };

                if (optionLists.Length == 1)
                {
                    yield return itemArray;
                }

                foreach (var nextCombination in GetCombinationsOfMultipleLists(optionLists.Skip(1).ToArray()))
                {
                    yield return itemArray.Concat(nextCombination);
                }
            }
        }
    }
}