public void ConstTestAssignAValueToACharAlreadyHasAValue()
        {
            Constant consta = new Constant();

            consta.ConstantSetFunction('a', 9);
            string constResult = consta.ConstantSetFunction('a', 10);

            Assert.AreEqual("Error", constResult);
        }
        public void ConstTestAssignAValueToACharDoesntHaveAValue()
        {
            Constant consta      = new Constant();
            string   constResult = consta.ConstantSetFunction('x', 3);

            Assert.AreEqual("Saved x as 3", constResult);
        }
        public void ConstTestAssignAValueToACharDoesntHaveAValueResultShouldNotBeNull()
        {
            Constant consta      = new Constant();
            string   constResult = consta.ConstantSetFunction('a', 0.3);

            Assert.IsNotNull(constResult);
        }
        public void ConstTestGetAnExistingValueIsNotNull()
        {
            Constant consta       = new Constant();
            string   constResult  = consta.ConstantSetFunction('b', 8);
            string   constResult2 = consta.ConstantGetFunction('b');

            Assert.IsNotNull(constResult2);
        }
        public void ConstTestCharPlusNum()
        {
            Constant consta = new Constant();

            consta.ConstantSetFunction('f', 4);
            string constResult = consta.constOperationFunction('f', "+", 5);

            Assert.AreEqual("=9", constResult);
        }
        public void ConstTestTypeOfOutputValue()
        {
            Constant consta = new Constant();

            consta.ConstantSetFunction('d', 4);
            string constResult = consta.ConstantGetFunction('d');

            Assert.AreEqual(typeof(string), constResult.GetType());
        }
        public void ConstTestGetAnExistingValue()
        {
            Constant consta = new Constant();

            consta.ConstantSetFunction('c', 9);
            string constResult = consta.ConstantGetFunction('c');

            Assert.AreEqual("9", constResult);
        }
        public void ConstTestCharDivideNum0()
        {
            Constant consta = new Constant();

            consta.ConstantSetFunction('j', 8);
            string constResult = consta.constOperationFunction('j', "/", 0);

            Assert.IsNull(constResult);
        }
        public void ConstTestCharDivideNum()
        {
            Constant consta = new Constant();

            consta.ConstantSetFunction('i', 10);
            string constResult = consta.constOperationFunction('i', "/", 5);

            Assert.AreEqual("=2", constResult);
        }
        public void ConstTestCharTimesNum()
        {
            Constant consta = new Constant();

            consta.ConstantSetFunction('h', 7);
            string constResult = consta.constOperationFunction('h', "*", 5);

            Assert.AreEqual("=35", constResult);
        }
        public void ConstTestCharMinusNum()
        {
            Constant consta = new Constant();

            consta.ConstantSetFunction('g', 7);
            string constResult = consta.constOperationFunction('g', "-", 5);

            Assert.AreEqual("=2", constResult);
        }