using NUnit.Framework; using Creek.HelpfulExtensions; using System.Collections.Generic; namespace UnitTests { public class IEnumerableExtensionTests { [SetUp] public void Setup() { } [Test] public void IsSubstringBetweenFirst() { List list = new List() { 1,2,3,4,5,6,7,8,9 }; string indexString = string.Empty; string valueString = string.Empty; foreach (var (item, index) in list.WithIndex()) { indexString += index; valueString += item; } Assert.AreEqual("012345678", indexString); Assert.AreEqual("123456789", valueString); } } }