@Test
	public void verifyExpressionWithExpression() {
		Context context = new Context();
		DataFactory factory = new DataFactory();
		IVPNumber a = factory.createIVPNumber();
		IVPNumber b = factory.createIVPNumber();
		IVPNumber c = factory.createIVPNumber();
		IVPNumber d = factory.createIVPNumber();

		a.setValueType(IVPValue.INTEGER_TYPE);
		b.setValueType(IVPValue.INTEGER_TYPE);
		c.setValueType(IVPValue.INTEGER_TYPE);
		d.setValueType(IVPValue.INTEGER_TYPE);

		context.addInt(a.getUniqueID(), 7);
		context.addInt(b.getUniqueID(), 10);
		context.addInt(c.getUniqueID(), 2);
		context.addInt(d.getUniqueID(), 2);

		Addition addition1 = factory.createAddition();
		addition1.setExpressionA(a.getUniqueID());
		addition1.setExpressionB(b.getUniqueID());

		Addition addition2 = factory.createAddition();
		addition2.setExpressionA(c.getUniqueID());
		addition2.setExpressionB(d.getUniqueID());

		Addition addition3 = factory.createAddition();
		addition3.setExpressionA(addition1.getUniqueID());
		addition3.setExpressionB(addition2.getUniqueID());

		HashMap map = new HashMap();
		map.put(addition1.getUniqueID(), addition1);
		map.put(addition2.getUniqueID(), addition2);
		map.put(addition3.getUniqueID(), addition3);
		map.put(a.getUniqueID(), a);
		map.put(b.getUniqueID(), b);
		map.put(c.getUniqueID(), c);
		map.put(d.getUniqueID(), d);
		// addition3(addition1(a + b) + addition2(c + d))
		// ((a + b) + (c + d))
		IVPNumber result = (IVPNumber) addition3.evaluate(context, map, factory);
		assertTrue(result.getValueType().equals(IVPValue.INTEGER_TYPE));
		assertTrue(context.getInt(result.getUniqueID()) == 21);
	}