System.Text.Tests.StringBuilderTests.Item_Get_Set_InvalidIndex C# (CSharp) Method

        public static void Item_Get_Set_InvalidIndex()
        {
            var builder = new StringBuilder("Hello");

            Assert.Throws<IndexOutOfRangeException>(() => builder[-1]); // Index < 0
            Assert.Throws<IndexOutOfRangeException>(() => builder[5]); // Index >= string.Length

            Assert.Throws<ArgumentOutOfRangeException>("index", () => builder[-1] = 'a'); // Index < 0
            Assert.Throws<ArgumentOutOfRangeException>("index", () => builder[5] = 'a'); // Index >= string.Length
        }