public void truncate()
{
PicoBuffer b;
b = new PicoBuffer(3);
b.append("1234567890");
b.truncate(6);
Assert.AreEqual(b.get_pos(), 4);
Assert.AreEqual(b.get_size(), 6);
Assert.AreEqual(b.to_string(), "1234");
b.delete();
}