### Question:
StringValue extends Value { @Override Value equal (Value v) { return new BooleanValue (mText.equals (v.toStringValue ().mText)); } StringValue(String text); @Override String toString();  }### Answer:
@Test public void testEqual () { assertEquals ("true", mEmptyString.equal (new StringValue ("")).toString ()); assertEquals ("true", mShortString.equal (new StringValue ("a")).toString ()); assertEquals ("false", mShortString.equal (mLongString).toString ()); }