@Override
    public ByteBuf copy() {
        return copy(readerIndex, readableBytes());
    }
@Test
    public void copyBoundaryCheck3() {
        assertThrows(IndexOutOfBoundsException.class, new Executable() {
            @Override
            public void execute() {
                buffer.copy(buffer.capacity() + 1, 0);
            }
        });
    }