System.Tests.StringTests.GetEnumerator_NonGeneric_IsIDisposable C# (CSharp) Method

        public static void GetEnumerator_NonGeneric_IsIDisposable()
        {
            IEnumerable enumerable = "abc";
            IEnumerator enumerator = enumerable.GetEnumerator();
            enumerator.MoveNext();

            IDisposable disposable = enumerable as IDisposable;
            if (disposable != null)
            {
                disposable.Dispose();
                Assert.Throws<NullReferenceException>(() => enumerator.Current);
                Assert.Throws<NullReferenceException>(() => enumerator.MoveNext());

                // Should be able to call dispose multiple times
                disposable.Dispose();
            }
        }