Formatting / Splitting string from Title Case to Delimited Words

TitleCaseToDelimited

namespace tests
{
	[TestClass]
	public class string_extension_tests
	{
		[TestMethod]
		public void when_formatting_title_case_to_delimited_but_the_delimiter_is_not_specified()
		{
			var s = "ThisIsTheDayThatTheLordHasMade";
			var formated = s.TitleCaseToDelimited();
			const string expected = "This Is The Day That The Lord Has Made";
			Assert.AreEqual(expected, formated);
		}

		[TestMethod]
		public void when_formatting_title_case_to_delimited_and_the_delimiter_is_specified()
		{
			var s = "ThisIsTheDayThatTheLordHasMade";
			var formated = s.TitleCaseToDelimited("_");
			const string expected = "This_Is_The_Day_That_The_Lord_Has_Made";
			Assert.AreEqual(expected, formated);
		}

	}

	/// <summary>
	/// String helpers
	/// </summary>
	public static class StringExtensions
	{
		/// <summary>
		/// It converts a string with the format of "ThisIsTheDayThatTheLordHasMade" to "This Is The Day The Lord Has Made"
		/// insprired by the conversation here: http://stackoverflow.com/questions/155303/net-how-can-you-split-a-caps-delimited-string-into-an-array
		/// Limitation: this will split all upper cased letters into separate words.  I don't have a need to for it now so go YAGNI 
		/// </summary>
		/// <param name="str"></param>
		/// <param name="delimiter"></param>
		/// <returns></returns>
		public static string TitleCaseToDelimited(this string str, params string[] delimiters)
		{
			//if there is no data, let's waste our breath
			if (string.IsNullOrWhiteSpace(str)) return str;
			//if not delimiter specified, use space
			string delimiter;
			if (delimiters.Length == 0 || string.IsNullOrWhiteSpace(delimiters[0])) delimiter = " ";
			else delimiter = delimiters[0];
			//regex does the magic
			return Regex.Replace(str, "(\\B[A-Z])", delimiter + "$1");
		}
	}
}