### Question:
RealValue extends Value { RealValue (double value) { mValue = value; } RealValue(double value);   RealValue(String value); @Override String toString();  }### Answer:
@Test public void testRealValue () { new RealValue (12.3); new RealValue (0.0); new RealValue (-12.3); new RealValue ("123"); new RealValue ("0.0"); new RealValue ("-123.0"); }