public void MathOperationsContainer_returns_default_operation_by_wrong_keyword()
        {
            var mathOperationsContainer = new MathOperationsContainer();

            var keyword = "&";

            var mathOperation = mathOperationsContainer.GetOperationOrDefault(keyword);

            Assert.Null(mathOperation);
        }
        public void MathOperationsContainer_returns_unary_minus_operation_by_keyword()
        {
            var mathOperationsContainer = new MathOperationsContainer();

            var keyword = "~";

            var stack = new Stack <double>();

            stack.Push(8.00);

            var mathOperation = mathOperationsContainer.GetOperationOrDefault(keyword);

            mathOperation.Operate(stack);

            Assert.Equal(1, mathOperation.Priority);
            Assert.Equal(OperationType.Unary, mathOperation.Type);

            Assert.Equal(-8.00, stack.Peek());
        }