public static BigDecimal fromWei(String number, Unit unit) {
        return fromWei(new BigDecimal(number), unit);
    }
@Test
    public void testFromWei() {
        assertEquals(
                Convert.fromWei("21000000000000", Convert.Unit.WEI),
                (new BigDecimal("21000000000000")));
        assertEquals(
                Convert.fromWei("21000000000000", Convert.Unit.KWEI),
                (new BigDecimal("21000000000")));
        assertEquals(
                Convert.fromWei("21000000000000", Convert.Unit.MWEI), (new BigDecimal("21000000")));
        assertEquals(
                Convert.fromWei("21000000000000", Convert.Unit.GWEI), (new BigDecimal("21000")));
        assertEquals(Convert.fromWei("21000000000000", Convert.Unit.SZABO), (new BigDecimal("21")));
        assertEquals(
                Convert.fromWei("21000000000000", Convert.Unit.FINNEY), (new BigDecimal("0.021")));
        assertEquals(
                Convert.fromWei("21000000000000", Convert.Unit.ETHER),
                (new BigDecimal("0.000021")));
        assertEquals(
                Convert.fromWei("21000000000000", Convert.Unit.KETHER),
                (new BigDecimal("0.000000021")));
        assertEquals(
                Convert.fromWei("21000000000000", Convert.Unit.METHER),
                (new BigDecimal("0.000000000021")));
        assertEquals(
                Convert.fromWei("21000000000000", Convert.Unit.GETHER),
                (new BigDecimal("0.000000000000021")));
    }