public void Configurer_Test()
        {
            var configurer = new TestConfigurer();
            ICalculator calculator = new CalculatorFactory(configurer).createInstance();

            double result = calculator.Compute("~3.3");
            Assert.AreEqual(3d, result);

            result = calculator.Compute("~3.3+2.8");
            Assert.AreEqual(5.8d, result);

            result = calculator.Compute("3.3+2.8~");
            Assert.AreEqual(4.1d, result);

            result = calculator.Compute("3.3+2.8~*2");
            Assert.AreEqual(4.9d, result, 0.00001);
        }