DoubleConverter doubleConverter = new DoubleConverter();
assertNull(doubleConverter.convert(null));
assertEquals(Double.valueOf(1), doubleConverter.convert(Integer.valueOf(1)));
assertEquals(Double.valueOf(1.73), doubleConverter.convert(Double.valueOf(1.73D)));
assertEquals(Double.valueOf(1.73), doubleConverter.convert("1.73"));
assertEquals(Double.valueOf(1.73), doubleConverter.convert(" 1.73 "));
assertEquals(Double.valueOf(1.73), doubleConverter.convert(" +1.73 "));
assertEquals(Double.valueOf(-1.73), doubleConverter.convert(" -1.73 "));
assertEquals(Double.valueOf(1.73), doubleConverter.convert(new BigDecimal("1.73")));