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

        public static void IndexOf_TurkishI()
        {
            string s = "Turkish I \u0131s TROUBL\u0130NG!";
            Helpers.PerformActionWithCulture(new CultureInfo("tr-TR"), () =>
            {
                string value = "\u0130";
                Assert.Equal(19, s.IndexOf(value));
                Assert.Equal(19, s.IndexOf(value, StringComparison.CurrentCulture));
                Assert.Equal(4, s.IndexOf(value, StringComparison.CurrentCultureIgnoreCase));
                Assert.Equal(19, s.IndexOf(value, StringComparison.Ordinal));
                Assert.Equal(19, s.IndexOf(value, StringComparison.OrdinalIgnoreCase));

                value = "\u0131";
                Assert.Equal(10, s.IndexOf(value, StringComparison.CurrentCulture));
                Assert.Equal(8, s.IndexOf(value, StringComparison.CurrentCultureIgnoreCase));
                Assert.Equal(10, s.IndexOf(value, StringComparison.Ordinal));
                Assert.Equal(10, s.IndexOf(value, StringComparison.OrdinalIgnoreCase));
            });
            Helpers.PerformActionWithCulture(CultureInfo.InvariantCulture, () =>
            {
                string value = "\u0130";
                Assert.Equal(19, s.IndexOf(value));
                Assert.Equal(19, s.IndexOf(value, StringComparison.CurrentCulture));
                Assert.Equal(19, s.IndexOf(value, StringComparison.CurrentCultureIgnoreCase));

                value = "\u0131";
                Assert.Equal(10, s.IndexOf(value, StringComparison.CurrentCulture));
                Assert.Equal(10, s.IndexOf(value, StringComparison.CurrentCultureIgnoreCase));
            });
            Helpers.PerformActionWithCulture(new CultureInfo("en-US"), () =>
            {
                string value = "\u0130";
                Assert.Equal(19, s.IndexOf(value));
                Assert.Equal(19, s.IndexOf(value, StringComparison.CurrentCulture));
                Assert.Equal(19, s.IndexOf(value, StringComparison.CurrentCultureIgnoreCase));

                value = "\u0131";
                Assert.Equal(10, s.IndexOf(value, StringComparison.CurrentCulture));
                Assert.Equal(10, s.IndexOf(value, StringComparison.CurrentCultureIgnoreCase));
            });
        }