String Comparison Unit Test Helper

TestHelper.cs

public static class TestHelpers
{
    public static void ShouldEqualWithDiff(this string actualValue, string expectedValue)
    {
        ShouldEqualWithDiff(actualValue, expectedValue, Console.Out);
    }

    public static void ShouldEqualWithDiff(this string actualValue, string expectedValue, TextWriter output)
    {
        if (actualValue.Equals(expectedValue, StringComparison.Ordinal)) return;

        output.WriteLine("Idx Expected  Actual");
        output.WriteLine("---------------------");
        int maxLen = Math.Max(actualValue.Length, expectedValue.Length);
        for (int i = 0; i < maxLen; i++)
        {
            output.Write(i);
            output.WritePadding(i);
            if (i < actualValue.Length)
            {
                output.WriteCharInfo(actualValue[i]);
            }
            else
                output.Write("      ");
            output.Write("\t");
            if (i < expectedValue.Length)
            {
                output.WriteCharInfo(expectedValue[i]);
            }
            else
                output.Write(" ");
            output.WriteLine();
        }
        output.WriteLine();
        Assert.Equal(actualValue, expectedValue);
    }

    private static void WriteCharInfo(this TextWriter output, char c)
    {
        output.Write((int)c);
        output.WritePadding(c);
        output.Write(c.ToSafeString());
    }

    // Assumes strings smaller than 1000 chars. Typical with unit tests.
    private static void WritePadding(this TextWriter output, int i)
    {
        output.Write(" ");
        if (i < 100)
        {
            output.Write(" ");
        }
        if (i < 10)
        {
            output.Write(" ");
        }
    }

    private static string ToSafeString(this char c)
    {
        if (Char.IsControl(c) || Char.IsWhiteSpace(c))
        {
            switch (c)
            {
                case '\r':
                    return @"\r";
                case '\n':
                    return @"\n";
                case '\t':
                    return @"\t";
                case '\a':
                    return @"\a";
                case '\v':
                    return @"\v";
                case '\f':
                    return @"\f";
                case ' ':
                    return @"\s";
                default:
                    return String.Format("\\u{0:X};", (int)c);
            }
        }
        return c.ToString(CultureInfo.InvariantCulture) + " ";
    }
}