using System;

using System.Collections.Generic;

using System.Linq;

using Microsoft.AspNetCore.Http;

using System.Security.Claims;

using Microsoft.VisualStudio.TestTools.UnitTesting;

using NSubstitute;

​

public class Program

{

    public static void Main()

    {

        new UnitTests().PerformUnitTest();

    }

}

​

// INSTRUCTIONS:

// The CustomerManager class will be used inside an ASP.NET aplication.  It has 

// an UpdateZip() method that updates a customer's zip code after validating it.  

// To do so, it retrieves a value from the current HttpContext and requires an 

// API call to validate the new zip.

//

// Refactor CustomerManager so that the PerformUnitTest() method can execute 

// without interacting with any of these external services and return two PASS lines

// in the console.  (If necessary, update other classes so that tests can execute.)

//

// UpdateZip() must be constructed in such a way that it can still interact with the 

// HttpContext and DbContext when run in the context of the real application.

// (It's not necessary to show how that will be done.)

//

[TestClass]

public class UnitTests

{

    [TestMethod]

    public void PerformUnitTest()

    {

        // Arrange

        var fakeHttpContextAccessor = Substitute.For<IHttpContextAccessor>();

        var fakeCustomerRepository = Substitute.For<ICustomerRepository>();

        var fakeZipCodeService = Substitute.For<IZipCodeService>();

        var sut = new CustomerManager(fakeHttpContextAccessor, fakeZipCodeService, fakeCustomerRepository);

​

        var claim = new Claim("CustomerId", "1");

        var claimsList = new List<Claim>() { claim };

        var validZipCodes = new List<string>() { "12345" };

​

        fakeHttpContextAccessor.HttpContext.User.Claims.Returns(claimsList);

        fakeZipCodeService.GetAllValidZipCodes().Returns(validZipCodes);

​

        // Act

        // No need to make any changes to this method below this line.

        var expected = true;

        var actual = sut.UpdateZip("12345"); // GOOD zip code

        var result = expected == actual ? "PASS" : "FAIL";

        Console.WriteLine(result);

        expected = false;

        actual = sut.UpdateZip("9999"); // BAD zip code

        result = expected == actual ? "PASS" : "FAIL";

        Console.WriteLine(result);

    }

}

​

public class CustomerManager

{

    private readonly IHttpContextAccessor _httpContextAccessor;

    private readonly IZipCodeService _zipCodeService;

    private readonly ICustomerRepository _customerRepository;

    public CustomerManager(IHttpContextAccessor httpContextAccessor, IZipCodeService zipCodeService, ICustomerRepository customerRepository) {

        _httpContextAccessor = httpContextAccessor;

        _zipCodeService = zipCodeService;

        _customerRepository = customerRepository;

    }

​

    public bool UpdateZip(string newZipCode)

    {

        var allZipCodes = _zipCodeService.GetAllValidZipCodes();

        if (allZipCodes.Contains(newZipCode))

        {

            var claim = _httpContextAccessor.HttpContext.User.Claims.Where(c => c.Type == "CustomerId").FirstOrDefault();

            var customerId = Convert.ToInt32(claim.Value);

            _customerRepository.UpdateZip(customerId, newZipCode);

            return true;

        }

        else

        {

            return false;

        }

    }

}

​

public interface IZipCodeService {

    public List<string> GetAllValidZipCodes();

}

​

public class ZipCodeService : IZipCodeService {

    private readonly string _apiEndpointUrl;

    private readonly IHttpClient _httpClient;

​

    public ZipCodeService(string apiEndpointUrl, IHttpClient httpClient) {

        _apiEndpointUrl = apiEndpointUrl;

        _httpClient = httpClient;

    }

​

    public List<string> GetAllValidZipCodes() {

        return _httpClient.Get<List<string>>(_apiEndpointUrl);

    }

}

​

public class Customer

{

    public int ID

    {

        get;

        set;

    }

​

    public string ZipCode

    {

        get;

        set;

    }

}

​

public interface ICustomerRepository {

    public void UpdateZip(int customerId, string newZipCode);   

}

​

public class CustomerRepository : ICustomerRepository

{

    private readonly IDbContext _db;

    public CustomerRepository(IDbContext dbContext) {

        _db = dbContext;

    }

    public void UpdateZip(int customerId, string newZipCode)

    {

        var customer = _db.Customers.SingleOrDefault(i => i.ID == customerId);

        customer.ZipCode = newZipCode;

    }

}

​

public interface IDbContext {

    public List<Customer> Customers {

        get;

        set;

    }

}

​

public class DbContext : IDbContext

{

    public List<Customer> Customers

    {

        get;

        set;

    }

}

​

public interface IHttpClient {

    public T Get<T>(string url);

}

​

public class HttpClient : IHttpClient

{

    public T Get<T>(string url)

    {

        // perform HTTP call and return response

        return default(T);

    }

}