sb.append((char[]) null); assertEquals("", sb.toString());
sb.setNullText("NULL").append((char[]) null); assertEquals("NULL", sb.toString());
    public void testAppend_CharArray() {        StrBuilder sb = new StrBuilder();                sb.append((char[]) null);        assertEquals("", sb.toString());        sb.append(new char[0]);        assertEquals("", sb.toString());        sb.append(new char[]{'f', 'o', 'o'});        assertEquals("foo", sb.toString());    }