Zak Parks - Coding exercise

InvestmentPerformanceWebAPI.Tests/InvestmentPerformanceWebAPI.Tests.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.4" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+    <PackageReference Include="xunit" Version="2.9.3" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.1.4" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\InvestmentPerformanceWebAPI\InvestmentPerformanceWebAPI.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Xunit" />
+  </ItemGroup>
+
+</Project>

InvestmentPerformanceWebAPI.Tests/UserInvestmentServiceTests.cs

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+using InvestmentPerformanceWebAPI.Database.Contexts;
+using InvestmentPerformanceWebAPI.Database.Models;
+using InvestmentPerformanceWebAPI.Services;
+using Microsoft.EntityFrameworkCore;
+
+namespace InvestmentPerformanceWebAPI.Tests
+{
+    public class UserInvestmentServiceTests
+    {
+        private static InvestmentDbContext CreateInMemoryContext()
+        {
+            var options = new DbContextOptionsBuilder<InvestmentDbContext>()
+                .UseInMemoryDatabase(Guid.NewGuid().ToString())
+                .Options;
+
+            var context = new InvestmentDbContext(options);
+
+            context.Investments.Add(new Investment
+            {
+                InvestmentId = 1,
+                UserId = 1,
+                Name = "Test",
+                Ticker = "TST",
+                NumberOfShares = 10m,
+                CostBasisPerShare = 100m,
+                CurrentPrice = 150m,
+                TimeOfPurchase = DateTime.UtcNow.AddDays(-100)
+            });
+
+            context.SaveChanges();
+            return context;
+        }
+
+        [Fact]
+        public async Task GetInvestment_Computes_Performance_Correctly()
+        {
+            // Arrange
+            using var context = CreateInMemoryContext();
+            var service = new UserInvestmentService(context);
+
+            // Act
+            var result = await service.GetInvestmentAsync(1, 1);
+
+            // Assert
+            Assert.NotNull(result);
+            Assert.Equal(1500m, result!.CurrentValue);      // 10 * 150
+            Assert.Equal(500m, result.TotalGainLoss);       // 1500 - 1000
+            Assert.Equal("ShortTerm", result.Term);         // 100 days < 365
+        }
+
+        [Fact]
+        public async Task GetInvestment_ReturnsNull_For_WrongUser()
+        {
+            using var context = CreateInMemoryContext();
+
+            // Add same investment for different user
+            context.Investments.Add(new Investment
+            {
+                InvestmentId = 2,
+                UserId = 2,
+                Name = "ForeignInvestment",
+                Ticker = "FI",
+                NumberOfShares = 10m,
+                CostBasisPerShare = 20m,
+                CurrentPrice = 22m,
+                TimeOfPurchase = DateTime.UtcNow.AddDays(-10)
+            });
+
+            context.SaveChanges();
+
+            var service = new UserInvestmentService(context);
+
+            // Act - user 1 tries to access investment 2 (owned by user 2)
+            var result = await service.GetInvestmentAsync(1, 2);
+
+            // Assert
+            Assert.Null(result);
+        }
+
+
+        [Fact]
+        public async Task GetInvestment_ReturnsNull_If_NotFound()
+        {
+            using var context = CreateInMemoryContext();
+            var service = new UserInvestmentService(context);
+
+            // Act
+            var result = await service.GetInvestmentAsync(1, 999);
+
+            // Assert
+            Assert.Null(result);
+        }
+
+        [Fact]
+        public async Task GetInvestment_Computes_LongTerm_Correctly()
+        {
+            using var context = CreateInMemoryContext();
+
+            // Modify existing seed to be long-term (> 365 days)
+            var investment = context.Investments.First();
+            investment.TimeOfPurchase = DateTime.UtcNow.AddDays(-400);
+            context.SaveChanges();
+
+            var service = new UserInvestmentService(context);
+
+            // Act
+            var result = await service.GetInvestmentAsync(1, 1);
+
+            // Assert
+            Assert.NotNull(result);
+            Assert.Equal("LongTerm", result!.Term);
+        }
+
+
+    }
+}

InvestmentPerformanceWebAPI/Controllers/UserInvestments.cs

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+using InvestmentPerformanceWebAPI.DTOs;
+using InvestmentPerformanceWebAPI.Interfaces;
+using Microsoft.AspNetCore.Mvc;
+
+namespace InvestmentPerformanceWebAPI.Controllers
+{
+    /// <summary>
+    /// API controller that exposes endpoints for querying user investments and investment details.
+    /// </summary>
+    [ApiController]
+    [Route("api/users/{userId:int}/investments")]
+    public class UserInvestmentsController(ILogger<UserInvestmentsController> logger, IUserInvestmentService userInvestments) : ControllerBase
+    {
+        private readonly ILogger<UserInvestmentsController> _logger = logger;
+        private readonly IUserInvestmentService _userInvestments = userInvestments;
+
+        /// <summary>
+        /// Gets a list of investments for a given user (id + name only).
+        /// </summary>
+        /// <param name="userId">Identifier of the user whose investments to retrieve.</param>
+        [HttpGet]
+        public async Task<ActionResult<UserInvestmentsDTO>> GetUserInvestments(int userId)
+        {
+            try
+            {
+                var dto = await _userInvestments.GetUserInvestmentsAsync(userId);
+                return Ok(dto);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error while fetching investments for userId {userId}", userId);
+                return Problem("Internal server error", statusCode: 500);
+            }
+        }
+
+        /// <summary>
+        /// Gets detailed information about a single investment for a given user.
+        /// </summary>
+        /// <param name="userId">Identifier of the owning user.</param>
+        /// <param name="investmentId">Identifier of the investment to retrieve.</param>
+        [HttpGet("{investmentId:int}")]
+        public async Task<ActionResult<InvestmentDTO>> GetInvestment(int userId, int investmentId)
+        {
+            try
+            {
+                var dto = await _userInvestments.GetInvestmentAsync(userId, investmentId);
+
+                if (dto is null)
+                {
+                    if (_logger.IsEnabled(LogLevel.Warning))
+                    {
+                        _logger.LogWarning("Investment {investmentId} for user {userId} not found", investmentId, userId);
+                    }
+                    return NotFound();
+                }
+
+                return Ok(dto);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error while fetching investment {investmentId} for userId {userId}", investmentId, userId);
+                return Problem("Internal server error", statusCode: 500);
+            }
+        }
+    }
+}

InvestmentPerformanceWebAPI/DTOs/InvestmentDTO.cs

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+namespace InvestmentPerformanceWebAPI.DTOs
+{
+    public class InvestmentDTO
+    {
+        public int InvestmentId { get; set; }
+        public string Name { get; set; } = string.Empty;
+        public string Ticker { get; set; } = string.Empty;
+        public decimal NumberOfShares { get; set; }
+        public decimal CostBasisPerShare { get; set; }
+        public decimal CurrentPrice { get; set; }
+
+        // Current total value of the position (NumberOfShares * CurrentPrice).
+        public decimal CurrentValue { get; set; }
+
+        // Investment term classification: "ShortTerm" or "LongTerm".
+        public string Term { get; set; } = string.Empty;
+
+        // CurrentValue - (NumberOfShares * CostBasisPerShare).
+        public decimal TotalGainLoss { get; set; }
+    }
+}

InvestmentPerformanceWebAPI/DTOs/UserInvestmentsDTO.cs

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+namespace InvestmentPerformanceWebAPI.DTOs
+{
+    /// <summary>
+    /// Response DTO representing a user's list of investments.
+    /// </summary>
+    public class UserInvestmentsDTO
+    {
+        public List<UserInvestmentSummaryDTO> Investments { get; set; } = [];
+    }
+
+    /// <summary>
+    /// Summary view for a single investment, used in list endpoints.
+    /// </summary>
+    public class UserInvestmentSummaryDTO
+    {
+        public int InvestmentId { get; set; }
+        public string Name { get; set; } = string.Empty;
+    }
+}

InvestmentPerformanceWebAPI/Database/Contexts/InvestmentDbContext.cs

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+using InvestmentPerformanceWebAPI.Database.Models;
+using Microsoft.EntityFrameworkCore;
+
+namespace InvestmentPerformanceWebAPI.Database.Contexts
+{
+    public class InvestmentDbContext(DbContextOptions<InvestmentDbContext> options) : DbContext(options)
+    {
+        public DbSet<User> Users { get; set; } = null!;
+        public DbSet<Investment> Investments { get; set; } = null!;
+
+        protected override void OnModelCreating(ModelBuilder modelBuilder)
+        {
+            modelBuilder.Entity<User>()
+                .HasMany(u => u.Investments)
+                .WithOne(i => i.User!)
+                .HasForeignKey(i => i.UserId);
+
+
+            // manually create some data entities
+            modelBuilder.Entity<User>().HasData(
+                new User { UserId = 1, Name = "Daniel Rivers" },
+                new User { UserId = 2, Name = "Sophia Bennett" },
+                new User { UserId = 3, Name = "Marcus Holt" },
+                new User { UserId = 4, Name = "Emma Caldwell" },
+                new User { UserId = 5, Name = "Jonathan Pierce" }
+            );
+
+
+            modelBuilder.Entity<Investment>().HasData(
+                new Investment
+                {
+                    InvestmentId = 1,
+                    UserId = 1,
+                    Name = "Berkshire Hathaway Inc.",
+                    Ticker = "BRK.B",
+                    NumberOfShares = 4,
+                    CostBasisPerShare = 290.75m,
+                    CurrentPrice = 365.40m,
+                    TimeOfPurchase = new DateTime(2022, 4, 12)
+                },
+                new Investment
+                {
+                    InvestmentId = 2,
+                    UserId = 1,
+                    Name = "Procter & Gamble Co.",
+                    Ticker = "PG",
+                    NumberOfShares = 18,
+                    CostBasisPerShare = 130.10m,
+                    CurrentPrice = 153.25m,
+                    TimeOfPurchase = new DateTime(2023, 11, 3)
+                },
+                new Investment
+                {
+                    InvestmentId = 3,
+                    UserId = 2,
+                    Name = "Costco Wholesale Corporation",
+                    Ticker = "COST",
+                    NumberOfShares = 6,
+                    CostBasisPerShare = 470.20m,
+                    CurrentPrice = 680.50m,
+                    TimeOfPurchase = new DateTime(2021, 8, 19)
+                },
+                new Investment
+                {
+                    InvestmentId = 4,
+                    UserId = 2,
+                    Name = "Walt Disney Company",
+                    Ticker = "DIS",
+                    NumberOfShares = 22,
+                    CostBasisPerShare = 92.15m,
+                    CurrentPrice = 101.85m,
+                    TimeOfPurchase = new DateTime(2024, 1, 7)
+                },
+                new Investment
+                {
+                    InvestmentId = 5,
+                    UserId = 3,
+                    Name = "Intel Corporation",
+                    Ticker = "INTC",
+                    NumberOfShares = 30,
+                    CostBasisPerShare = 28.00m,
+                    CurrentPrice = 36.75m,
+                    TimeOfPurchase = new DateTime(2023, 5, 16)
+                },
+                new Investment
+                {
+                    InvestmentId = 6,
+                    UserId = 3,
+                    Name = "Chevron Corporation",
+                    Ticker = "CVX",
+                    NumberOfShares = 12,
+                    CostBasisPerShare = 148.50m,
+                    CurrentPrice = 159.95m,
+                    TimeOfPurchase = new DateTime(2022, 2, 27)
+                },
+                new Investment
+                {
+                    InvestmentId = 7,
+                    UserId = 4,
+                    Name = "UnitedHealth Group Incorporated",
+                    Ticker = "UNH",
+                    NumberOfShares = 3,
+                    CostBasisPerShare = 460.00m,
+                    CurrentPrice = 529.40m,
+                    TimeOfPurchase = new DateTime(2023, 8, 24)
+                },
+                new Investment
+                {
+                    InvestmentId = 8,
+                    UserId = 4,
+                    Name = "PepsiCo, Inc.",
+                    Ticker = "PEP",
+                    NumberOfShares = 14,
+                    CostBasisPerShare = 165.25m,
+                    CurrentPrice = 172.45m,
+                    TimeOfPurchase = new DateTime(2021, 12, 10)
+                },
+                new Investment
+                {
+                    InvestmentId = 9,
+                    UserId = 5,
+                    Name = "AbbVie Inc.",
+                    Ticker = "ABBV",
+                    NumberOfShares = 9,
+                    CostBasisPerShare = 112.80m,
+                    CurrentPrice = 157.60m,
+                    TimeOfPurchase = new DateTime(2024, 3, 5)
+                },
+                new Investment
+                {
+                    InvestmentId = 10,
+                    UserId = 5,
+                    Name = "Ford Motor Company",
+                    Ticker = "F",
+                    NumberOfShares = 40,
+                    CostBasisPerShare = 11.45m,
+                    CurrentPrice = 13.90m,
+                    TimeOfPurchase = new DateTime(2022, 9, 22)
+                }
+            );
+        }
+    }
+}