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Who cares about Domain Rules?

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20 Nov 2006MIT12 min read 96.3K   85   118  
With this article, I am evolving a domain problem towards the best possible solution.
 
/*
 * Created by: Maruis Marais
 * Created: Saturday, 11 November 2006
 */

using NMock2;

using NUnit.Framework;

namespace BusinessRules.Evolution_Five.Tests
{
    [TestFixture]
    public class IncomeTaxEngineFixture
    {
        private Mockery mocks = null;
        private ICurrentCultureInfo currentCulture = null;
        private IIncomeTaxEngine incomeTaxEngine = null;

        /// <summary>
        /// The Setup method is called before each test method is called. 
        /// </summary>
        [SetUp]
        public void Setup()
        {
            mocks = new Mockery();
            currentCulture = mocks.NewMock<ICurrentCultureInfo>();
        }

        [Test]
        public void TaxRateCalculatedCorrectlyForUSABands()
        {
            // Setup expectations for our mock.
            Expect.Once.On(currentCulture).GetProperty("CurrentCultureName").Will(Return.Value("en-US"));

            // Create the instance of the income tax engine
            incomeTaxEngine = new IncomeTaxEngine(currentCulture);

            // Validate the income tax engine works as expected

            Assert.AreEqual(0.10, incomeTaxEngine.CalculateTaxRate(0.0));
            Assert.AreEqual(0.10, incomeTaxEngine.CalculateTaxRate(1500.00));
            Assert.AreEqual(0.10, incomeTaxEngine.CalculateTaxRate(7550.99));

            Assert.AreEqual(0.15, incomeTaxEngine.CalculateTaxRate(7551.00));
            Assert.AreEqual(0.15, incomeTaxEngine.CalculateTaxRate(28000.00));
            Assert.AreEqual(0.15, incomeTaxEngine.CalculateTaxRate(30650.99));

            Assert.AreEqual(0.25, incomeTaxEngine.CalculateTaxRate(30651.00));
            Assert.AreEqual(0.25, incomeTaxEngine.CalculateTaxRate(65000.00));
            Assert.AreEqual(0.25, incomeTaxEngine.CalculateTaxRate(74200.99));

            Assert.AreEqual(0.28, incomeTaxEngine.CalculateTaxRate(74201.00));
            Assert.AreEqual(0.28, incomeTaxEngine.CalculateTaxRate(84526.00));
            Assert.AreEqual(0.28, incomeTaxEngine.CalculateTaxRate(154800.99));

            Assert.AreEqual(0.33, incomeTaxEngine.CalculateTaxRate(154801.00));
            Assert.AreEqual(0.33, incomeTaxEngine.CalculateTaxRate(205456.44));
            Assert.AreEqual(0.33, incomeTaxEngine.CalculateTaxRate(336550.99));

            Assert.AreEqual(0.35, incomeTaxEngine.CalculateTaxRate(336551.00));
            Assert.AreEqual(0.35, incomeTaxEngine.CalculateTaxRate(536551.00));
            Assert.AreEqual(0.35, incomeTaxEngine.CalculateTaxRate(double.MaxValue - 0.01));
        }

        [Test]
        public void TaxLiabilityCalculatedCorrectlyForUSABands()
        {
            // Setup expectations for our mock.
            Expect.Once.On(currentCulture).GetProperty("CurrentCultureName").Will(Return.Value("en-US"));

            // Create the instance of the income tax engine
            incomeTaxEngine = new IncomeTaxEngine(currentCulture);

            // Validate the income tax engine works as expected

            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(0.0), 2.0);
            Assert.AreEqual(150.00, incomeTaxEngine.CalculateTaxLiability(1500.00), 2.0);
            Assert.AreEqual(755.10, incomeTaxEngine.CalculateTaxLiability(7550.99), 2.0);

            Assert.AreEqual(755.10, incomeTaxEngine.CalculateTaxLiability(7551.00), 2.0);
            Assert.AreEqual(3822.45, incomeTaxEngine.CalculateTaxLiability(28000.00), 2.0);
            Assert.AreEqual(4220.10, incomeTaxEngine.CalculateTaxLiability(30650.99), 2.0);

            Assert.AreEqual(4220.10, incomeTaxEngine.CalculateTaxLiability(30651.00), 2.0);
            Assert.AreEqual(12807.35, incomeTaxEngine.CalculateTaxLiability(65000.00), 2.0);
            Assert.AreEqual(15107.60, incomeTaxEngine.CalculateTaxLiability(74200.99), 2.0);

            Assert.AreEqual(15107.60, incomeTaxEngine.CalculateTaxLiability(74201.00), 2.0);
            Assert.AreEqual(17998.60, incomeTaxEngine.CalculateTaxLiability(84526.00), 2.0);
            Assert.AreEqual(37675.60, incomeTaxEngine.CalculateTaxLiability(154800.99), 2.0);

            Assert.AreEqual(37675.60, incomeTaxEngine.CalculateTaxLiability(154801.00), 2.0);
            Assert.AreEqual(54391.89, incomeTaxEngine.CalculateTaxLiability(205456.44), 2.0);
            Assert.AreEqual(97653.09, incomeTaxEngine.CalculateTaxLiability(336550.99), 2.0);

            Assert.AreEqual(97653.09, incomeTaxEngine.CalculateTaxLiability(336551.00), 2.0);
            Assert.AreEqual(167653.09, incomeTaxEngine.CalculateTaxLiability(536551.00), 2.0);
            Assert.AreEqual(6.2919259720181043E+307, incomeTaxEngine.CalculateTaxLiability(double.MaxValue - 0.01), 2.0);
        }

        [Test]
        public void TaxRateCalculatedCorrectlyForAustralianBands()
        {
            // Setup expectations for our mock.
            Expect.Once.On(currentCulture).GetProperty("CurrentCultureName").Will(Return.Value("en-AU"));

            // Create the instance of the income tax engine
            incomeTaxEngine = new IncomeTaxEngine(currentCulture);

            // Validate the income tax engine works as expected

            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxRate(0.0));
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxRate(1500.00));
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxRate(6000.99));

            Assert.AreEqual(0.15, incomeTaxEngine.CalculateTaxRate(6001.00));
            Assert.AreEqual(0.15, incomeTaxEngine.CalculateTaxRate(22258.32));
            Assert.AreEqual(0.15, incomeTaxEngine.CalculateTaxRate(25000.99));

            Assert.AreEqual(0.30, incomeTaxEngine.CalculateTaxRate(25001.00));
            Assert.AreEqual(0.30, incomeTaxEngine.CalculateTaxRate(65000.00));
            Assert.AreEqual(0.30, incomeTaxEngine.CalculateTaxRate(75000.99));

            Assert.AreEqual(0.40, incomeTaxEngine.CalculateTaxRate(75001.00));
            Assert.AreEqual(0.40, incomeTaxEngine.CalculateTaxRate(84526.00));
            Assert.AreEqual(0.40, incomeTaxEngine.CalculateTaxRate(150000.99));

            Assert.AreEqual(0.45, incomeTaxEngine.CalculateTaxRate(150001.00));
            Assert.AreEqual(0.45, incomeTaxEngine.CalculateTaxRate(205456.44));
            Assert.AreEqual(0.45, incomeTaxEngine.CalculateTaxRate(double.MaxValue - 0.01));
        }

        [Test]
        public void TaxLiabilityCalculatedCorrectlyForAustralianBands()
        {
            // Setup expectations for our mock.
            Expect.Once.On(currentCulture).GetProperty("CurrentCultureName").Will(Return.Value("en-AU"));

            // Create the instance of the income tax engine
            incomeTaxEngine = new IncomeTaxEngine(currentCulture);

            // Validate the income tax engine works as expected

            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(0.0), 2.0);
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(1500.00), 2.0);
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(6000.99), 2.0);

            Assert.AreEqual(0.15, incomeTaxEngine.CalculateTaxLiability(6001.00), 2.0);
            Assert.AreEqual(2438.60, incomeTaxEngine.CalculateTaxLiability(22258.32), 2.0);
            Assert.AreEqual(2850.00, incomeTaxEngine.CalculateTaxLiability(25000.99), 2.0);

            Assert.AreEqual(2850.00, incomeTaxEngine.CalculateTaxLiability(25001.00), 2.0);
            Assert.AreEqual(14849.70, incomeTaxEngine.CalculateTaxLiability(65000.00), 2.0);
            Assert.AreEqual(17850.00, incomeTaxEngine.CalculateTaxLiability(75000.99), 2.0);

            Assert.AreEqual(17850.00, incomeTaxEngine.CalculateTaxLiability(75001.00), 2.0);
            Assert.AreEqual(21660.00, incomeTaxEngine.CalculateTaxLiability(84526.00), 2.0);
            Assert.AreEqual(47850.00, incomeTaxEngine.CalculateTaxLiability(150000.99), 2.0);

            Assert.AreEqual(47850.00, incomeTaxEngine.CalculateTaxLiability(150001.00), 2.0);
            Assert.AreEqual(72804.94, incomeTaxEngine.CalculateTaxLiability(205456.44), 2.0);
            Assert.AreEqual(8.0896191068804208E+307, incomeTaxEngine.CalculateTaxLiability(double.MaxValue - 0.01), 2.0);
        }

        [Test]
        public void TaxRateCalculatedCorrectlyForNewZelandBands()
        {
            // Setup expectations for our mock.
            Expect.Once.On(currentCulture).GetProperty("CurrentCultureName").Will(Return.Value("en-NZ"));

            // Create the instance of the income tax engine
            incomeTaxEngine = new IncomeTaxEngine(currentCulture);

            // Validate the income tax engine works as expected

            Assert.AreEqual(0.195, incomeTaxEngine.CalculateTaxRate(0.0));
            Assert.AreEqual(0.195, incomeTaxEngine.CalculateTaxRate(9500.00));
            Assert.AreEqual(0.195, incomeTaxEngine.CalculateTaxRate(19500.00));
            Assert.AreEqual(0.195, incomeTaxEngine.CalculateTaxRate(19500.99));

            Assert.AreEqual(0.33, incomeTaxEngine.CalculateTaxRate(19501.00));
            Assert.AreEqual(0.33, incomeTaxEngine.CalculateTaxRate(28000.00));
            Assert.AreEqual(0.33, incomeTaxEngine.CalculateTaxRate(60000.00));
            Assert.AreEqual(0.33, incomeTaxEngine.CalculateTaxRate(60000.99));

            Assert.AreEqual(0.39, incomeTaxEngine.CalculateTaxRate(60001.00));
            Assert.AreEqual(0.39, incomeTaxEngine.CalculateTaxRate(65000.00));
            Assert.AreEqual(0.39, incomeTaxEngine.CalculateTaxRate(999999999.00));
        }

        [Test]
        public void TaxLiabilityCalculatedCorrectlyForNewZelandBands()
        {
            // Setup expectations for our mock.
            Expect.Once.On(currentCulture).GetProperty("CurrentCultureName").Will(Return.Value("en-NZ"));

            // Create the instance of the income tax engine
            incomeTaxEngine = new IncomeTaxEngine(currentCulture);

            // Validate the income tax engine works as expected

            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(0.0), 2.0);
            Assert.AreEqual(1852.50, incomeTaxEngine.CalculateTaxLiability(9500.00), 2.0);
            Assert.AreEqual(3802.50, incomeTaxEngine.CalculateTaxLiability(19500.00), 2.0);
            Assert.AreEqual(3802.69, incomeTaxEngine.CalculateTaxLiability(19500.99), 2.0);

            Assert.AreEqual(3802.70, incomeTaxEngine.CalculateTaxLiability(19501.00), 2.0);
            Assert.AreEqual(6607.36, incomeTaxEngine.CalculateTaxLiability(28000.00), 2.0);
            Assert.AreEqual(17167.36, incomeTaxEngine.CalculateTaxLiability(60000.00), 2.0);
            Assert.AreEqual(17167.69, incomeTaxEngine.CalculateTaxLiability(60000.99), 2.0);

            Assert.AreEqual(17167.69, incomeTaxEngine.CalculateTaxLiability(60001.00), 2.0);
            Assert.AreEqual(19117.30, incomeTaxEngine.CalculateTaxLiability(65000.00), 2.0);
            Assert.AreEqual(389993766.91, incomeTaxEngine.CalculateTaxLiability(999999999.00), 2.0);
            Assert.AreEqual(7.0110032259630313E+307, incomeTaxEngine.CalculateTaxLiability(double.MaxValue - 0.01), 2.0);
        }

        [Test]
        public void TaxRateCalculatedCorrectlyForNonExceptionalBehaviorTaxEngine()
        {
            // Setup expectations for our mock.
            Expect.Once.On(currentCulture).GetProperty("CurrentCultureName").Will(Return.Value("en-ZA"));

            // Create the instance of the income tax engine
            incomeTaxEngine = new IncomeTaxEngine(currentCulture);

            // Validate the income tax engine works as expected

            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxRate(0.0));
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxRate(9500.00));
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxRate(19500.00));
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxRate(19500.99));

            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxRate(19501.00));
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxRate(28000.00));
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxRate(60000.00));
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxRate(60000.99));

            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxRate(60001.00));
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxRate(65000.00));
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxRate(999999999.00));
        }

        [Test]
        public void TaxLiabilityCalculatedCorrectlyForNonExceptionalBehaviorTaxEngine()
        {
            // Setup expectations for our mock.
            Expect.Once.On(currentCulture).GetProperty("CurrentCultureName").Will(Return.Value("en-ZA"));

            // Create the instance of the income tax engine
            incomeTaxEngine = new IncomeTaxEngine(currentCulture);

            // Validate the income tax engine works as expected

            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(0.0), 2.0);
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(9500.00), 2.0);
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(19500.00), 2.0);
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(19500.99), 2.0);

            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(19501.00), 2.0);
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(28000.00), 2.0);
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(60000.00), 2.0);
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(60000.99), 2.0);

            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(60001.00), 2.0);
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(65000.00), 2.0);
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(999999999.00), 2.0);
            Assert.AreEqual(0.0, incomeTaxEngine.CalculateTaxLiability(double.MaxValue - 0.01), 2.0);
        }

        /// <summary>
        /// The Teardown method is called after each test method is called. 
        /// So we validate all the expectations have been met.
        /// </summary>
        [TearDown]
        public void Teardown()
        {
            mocks.VerifyAllExpectationsHaveBeenMet();
        }
    }
}

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This article, along with any associated source code and files, is licensed under The MIT License


Written By
Maruis Marais
Web Developer
New Zealand New Zealand
This member has not yet provided a Biography. Assume it's interesting and varied, and probably something to do with programming.

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Posted 20 Nov 2006

Article Copyright 2006 by Maruis Marais
Everything else Copyright © CodeProject, 1999-2024

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