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

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

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

		Subtraction subtraction1 = factory.createSubtraction();
		subtraction1.setExpressionA(a.getUniqueID());
		subtraction1.setExpressionB(b.getUniqueID());

		Subtraction subtraction2 = factory.createSubtraction();
		subtraction2.setExpressionA(c.getUniqueID());
		subtraction2.setExpressionB(subtraction1.getUniqueID());

		HashMap map = new HashMap();
		map.put(subtraction1.getUniqueID(), subtraction1);
		map.put(subtraction2.getUniqueID(), subtraction2);
		map.put(a.getUniqueID(), a);
		map.put(b.getUniqueID(), b);
		map.put(c.getUniqueID(), c);
		// subtraction2(c - subtraction1(a - b))
		// c - (a - b)
		IVPNumber result = (IVPNumber) subtraction2.evaluate(context, map, factory);
		assertTrue(result.getValueType().equals(IVPValue.INTEGER_TYPE));
		assertTrue(context.getInt(result.getUniqueID()) == 5);
	}