// Test addition
MathExpressionImpl mathTest = new AddImpl(null, null);
mathTest.setExpression1(testAttribute1);
mathTest.setExpression2(testAttribute2);
assertEquals(new Integer(6), mathTest.evaluate(testObject,
Integer.class));
// Test subtraction
mathTest = new SubtractImpl(null, null);
mathTest.setExpression1(testAttribute1);