@Override
    public StringBuffer format(double number, StringBuffer toAppendTo, FieldPosition pos) {
        int initLength = toAppendTo.length();
        super.format(number, toAppendTo, pos);
        return pad(toAppendTo, initLength);
    }
@Test
    void format() {
        PaddingDecimalFormat format = new PaddingDecimalFormat("0.0", 7);
        assertThat(format.format(1L)).isEqualTo("    1.0");
        assertThat(format.format(1000L)).isEqualTo(" 1000.0");
        assertThat(format.format(10000000L)).isEqualTo("10000000.0");
    }