public void op_PadRight_int_char(string text,
                                         int width,
                                         char padding)
        {
            var expected = new MutableString((text ?? string.Empty).PadRight(width, '_'));
            var actual = new MutableString(text);

            Assert.Same(actual, actual.PadRight(width, padding));

            Assert.Equal(expected, actual);
        }