public void IncreasingIndentation_ByMustBeGreaterThanZero()
{
var sw = new StringWriter();
var iw = new IndentingTextWriter(sw, " ");
Assert.Throws <ArgumentOutOfRangeException>(() => iw.IncreaseIndentation(0));
Assert.Throws <ArgumentOutOfRangeException>(() => iw.IncreaseIndentation(-42));
}