public void SubtractionInteger_TwoIntegers_ReturnsCorrectResultOfSubtraction(int input1, int input2, int expected)
{
IntegerLiteralExpression intLit1 = new IntegerLiteralExpression(input1.ToString(), 1, 1);
IntegerLiteralExpression intLit2 = new IntegerLiteralExpression(input2.ToString(), 2, 2);
SubtractionExpression subExpr = new SubtractionExpression(intLit1, intLit2, 1, 1);
IInterpreterInteger parent = Substitute.For <IInterpreterInteger>();
parent.DispatchInt(intLit1, Arg.Any <List <object> >()).Returns(input1);
parent.DispatchInt(intLit2, Arg.Any <List <object> >()).Returns(input2);
IntegerHelper integerHelper = SetUpHelper(parent);
int res = integerHelper.SubtractionInteger(subExpr, new List <object>());
Assert.AreEqual(expected, res);
}