public void DoOperationExisting_Test()
        {
            var operand1     = 3;
            var operand2     = 4;
            var calculator   = new ConsoleCalculator(1, 2, operand1, operand2, CalculatorOperators.Add);
            var actualResult = calculator.DoOperation();

            Assert.AreEqual(operand1 + operand2, calculator.Result);
            Assert.AreEqual(ResultStatus.OK, actualResult);
        }