diff --git a/MoneyMap.Tests/MoneyMap.Tests.csproj b/MoneyMap.Tests/MoneyMap.Tests.csproj
new file mode 100644
index 0000000..3b7f223
--- /dev/null
+++ b/MoneyMap.Tests/MoneyMap.Tests.csproj
@@ -0,0 +1,27 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.2" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="9.0.10" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
+    <PackageReference Include="Moq" Version="4.20.72" />
+    <PackageReference Include="xunit" Version="2.9.2" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Xunit" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\MoneyMap\MoneyMap.csproj" />
+  </ItemGroup>
+
+</Project>
diff --git a/MoneyMap.Tests/Services/AccountServiceTests.cs b/MoneyMap.Tests/Services/AccountServiceTests.cs
new file mode 100644
index 0000000..498ebfa
--- /dev/null
+++ b/MoneyMap.Tests/Services/AccountServiceTests.cs
@@ -0,0 +1,237 @@
+using MoneyMap.Models;
+using MoneyMap.Services;
+using MoneyMap.Tests.TestHelpers;
+using Xunit;
+
+namespace MoneyMap.Tests.Services;
+
+public class AccountServiceTests
+{
+    [Fact]
+    public async Task GetAllAccountsWithStatsAsync_ReturnsAccountsWithTransactionCounts()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new AccountService(context);
+
+        var account1 = new Account
+        {
+            Id = 1,
+            Institution = "Bank A",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "John Doe"
+        };
+        var account2 = new Account
+        {
+            Id = 2,
+            Institution = "Bank B",
+            AccountType = AccountType.Savings,
+            Last4 = "5678",
+            Owner = "Jane Smith"
+        };
+        context.Accounts.AddRange(account1, account2);
+
+        var transaction1 = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1
+        };
+        var transaction2 = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -25.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1
+        };
+        context.Transactions.AddRange(transaction1, transaction2);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.GetAllAccountsWithStatsAsync();
+
+        // Assert
+        Assert.Equal(2, result.Count);
+        var account1Stats = result.First(a => a.Id == 1);
+        Assert.Equal(2, account1Stats.TransactionCount);
+        var account2Stats = result.First(a => a.Id == 2);
+        Assert.Equal(0, account2Stats.TransactionCount);
+    }
+
+    [Fact]
+    public async Task CanDeleteAccountAsync_ReturnsFalse_WhenAccountHasTransactions()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new AccountService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var transaction = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1
+        };
+        context.Transactions.Add(transaction);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.CanDeleteAccountAsync(1);
+
+        // Assert
+        Assert.False(result.CanDelete);
+        Assert.Contains("transaction", result.Reason, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public async Task CanDeleteAccountAsync_ReturnsTrue_WhenAccountHasNoTransactions()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new AccountService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.CanDeleteAccountAsync(1);
+
+        // Assert
+        Assert.True(result.CanDelete);
+    }
+
+    [Fact]
+    public async Task DeleteAccountAsync_SuccessfullyDeletesAccount_WhenNoTransactions()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new AccountService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.DeleteAccountAsync(1);
+
+        // Assert
+        Assert.True(result.Success);
+        Assert.Empty(context.Accounts);
+    }
+
+    [Fact]
+    public async Task DeleteAccountAsync_FailsToDelete_WhenAccountHasTransactions()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new AccountService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var transaction = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1
+        };
+        context.Transactions.Add(transaction);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.DeleteAccountAsync(1);
+
+        // Assert
+        Assert.False(result.Success);
+        Assert.Single(context.Accounts);
+    }
+
+    [Fact]
+    public async Task GetAccountDetailsAsync_ReturnsFullDetails_WithCardsAndCounts()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new AccountService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var card = new Card
+        {
+            Id = 1,
+            AccountId = 1,
+            Issuer = "VISA",
+            Last4 = "9999",
+            Owner = "Test Owner"
+        };
+        context.Cards.Add(card);
+
+        var transaction = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            CardId = 1
+        };
+        context.Transactions.Add(transaction);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.GetAccountDetailsAsync(1);
+
+        // Assert
+        Assert.NotNull(result);
+        Assert.Equal(1, result.Account.Id);
+        Assert.Single(result.Cards);
+        Assert.Equal(1, result.Cards[0].TransactionCount);
+        Assert.Equal(1, result.TransactionCount);
+    }
+}
diff --git a/MoneyMap.Tests/Services/CardServiceTests.cs b/MoneyMap.Tests/Services/CardServiceTests.cs
new file mode 100644
index 0000000..2e574d1
--- /dev/null
+++ b/MoneyMap.Tests/Services/CardServiceTests.cs
@@ -0,0 +1,232 @@
+using MoneyMap.Models;
+using MoneyMap.Services;
+using MoneyMap.Tests.TestHelpers;
+using Xunit;
+
+namespace MoneyMap.Tests.Services;
+
+public class CardServiceTests
+{
+    [Fact]
+    public async Task GetAllCardsWithStatsAsync_ReturnsCardsWithTransactionCounts()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new CardService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var card1 = new Card
+        {
+            Id = 1,
+            AccountId = 1,
+            Issuer = "VISA",
+            Last4 = "1111",
+            Owner = "John Doe"
+        };
+        var card2 = new Card
+        {
+            Id = 2,
+            AccountId = 1,
+            Issuer = "Mastercard",
+            Last4 = "2222",
+            Owner = "Jane Smith"
+        };
+        context.Cards.AddRange(card1, card2);
+
+        var transaction = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            CardId = 1
+        };
+        context.Transactions.Add(transaction);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.GetAllCardsWithStatsAsync();
+
+        // Assert
+        Assert.Equal(2, result.Count);
+        var card1Stats = result.First(c => c.Card.Id == 1);
+        Assert.Equal(1, card1Stats.TransactionCount);
+        var card2Stats = result.First(c => c.Card.Id == 2);
+        Assert.Equal(0, card2Stats.TransactionCount);
+    }
+
+    [Fact]
+    public async Task CanDeleteCardAsync_ReturnsFalse_WhenCardHasTransactions()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new CardService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var card = new Card
+        {
+            Id = 1,
+            AccountId = 1,
+            Issuer = "VISA",
+            Last4 = "9999",
+            Owner = "Test Owner"
+        };
+        context.Cards.Add(card);
+
+        var transaction = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            CardId = 1
+        };
+        context.Transactions.Add(transaction);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.CanDeleteCardAsync(1);
+
+        // Assert
+        Assert.False(result.CanDelete);
+        Assert.Contains("transaction", result.Reason, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public async Task CanDeleteCardAsync_ReturnsTrue_WhenCardHasNoTransactions()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new CardService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var card = new Card
+        {
+            Id = 1,
+            AccountId = 1,
+            Issuer = "VISA",
+            Last4 = "9999",
+            Owner = "Test Owner"
+        };
+        context.Cards.Add(card);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.CanDeleteCardAsync(1);
+
+        // Assert
+        Assert.True(result.CanDelete);
+    }
+
+    [Fact]
+    public async Task DeleteCardAsync_SuccessfullyDeletesCard_WhenNoTransactions()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new CardService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var card = new Card
+        {
+            Id = 1,
+            AccountId = 1,
+            Issuer = "VISA",
+            Last4 = "9999",
+            Owner = "Test Owner"
+        };
+        context.Cards.Add(card);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.DeleteCardAsync(1);
+
+        // Assert
+        Assert.True(result.Success);
+        Assert.Empty(context.Cards);
+    }
+
+    [Fact]
+    public async Task DeleteCardAsync_FailsToDelete_WhenCardHasTransactions()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new CardService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var card = new Card
+        {
+            Id = 1,
+            AccountId = 1,
+            Issuer = "VISA",
+            Last4 = "9999",
+            Owner = "Test Owner"
+        };
+        context.Cards.Add(card);
+
+        var transaction = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            CardId = 1
+        };
+        context.Transactions.Add(transaction);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.DeleteCardAsync(1);
+
+        // Assert
+        Assert.False(result.Success);
+        Assert.Single(context.Cards);
+    }
+}
diff --git a/MoneyMap.Tests/Services/MerchantServiceTests.cs b/MoneyMap.Tests/Services/MerchantServiceTests.cs
new file mode 100644
index 0000000..985352d
--- /dev/null
+++ b/MoneyMap.Tests/Services/MerchantServiceTests.cs
@@ -0,0 +1,189 @@
+using MoneyMap.Models;
+using MoneyMap.Services;
+using MoneyMap.Tests.TestHelpers;
+using Xunit;
+
+namespace MoneyMap.Tests.Services;
+
+public class MerchantServiceTests
+{
+    [Fact]
+    public async Task GetOrCreateAsync_CreatesNewMerchant_WhenDoesNotExist()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new MerchantService(context);
+
+        // Act
+        var result = await service.GetOrCreateAsync("Walmart");
+
+        // Assert
+        Assert.NotNull(result);
+        Assert.Equal("Walmart", result.Name);
+        Assert.Single(context.Merchants);
+    }
+
+    [Fact]
+    public async Task GetOrCreateAsync_ReturnsExistingMerchant_WhenExists()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new MerchantService(context);
+
+        var existingMerchant = new Merchant { Id = 1, Name = "Walmart" };
+        context.Merchants.Add(existingMerchant);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.GetOrCreateAsync("Walmart");
+
+        // Assert
+        Assert.NotNull(result);
+        Assert.Equal(1, result.Id);
+        Assert.Single(context.Merchants);
+    }
+
+    [Fact]
+    public async Task GetAllMerchantsWithStatsAsync_ReturnsMerchantsWithStats()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new MerchantService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var merchant1 = new Merchant { Id = 1, Name = "Walmart" };
+        var merchant2 = new Merchant { Id = 2, Name = "Target" };
+        context.Merchants.AddRange(merchant1, merchant2);
+
+        var transaction = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            MerchantId = 1
+        };
+        context.Transactions.Add(transaction);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.GetAllMerchantsWithStatsAsync();
+
+        // Assert
+        Assert.Equal(2, result.Count);
+        var walmart = result.First(m => m.Name == "Walmart");
+        Assert.Equal(1, walmart.TransactionCount);
+        var target = result.First(m => m.Name == "Target");
+        Assert.Equal(0, target.TransactionCount);
+    }
+
+    [Fact]
+    public async Task UpdateMerchantAsync_SuccessfullyUpdatesName()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new MerchantService(context);
+
+        var merchant = new Merchant { Id = 1, Name = "Walmart" };
+        context.Merchants.Add(merchant);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.UpdateMerchantAsync(1, "Walmart Supercenter");
+
+        // Assert
+        Assert.True(result.Success);
+        var updated = await context.Merchants.FindAsync(1);
+        Assert.Equal("Walmart Supercenter", updated!.Name);
+    }
+
+    [Fact]
+    public async Task UpdateMerchantAsync_FailsWhenDuplicateName()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new MerchantService(context);
+
+        var merchant1 = new Merchant { Id = 1, Name = "Walmart" };
+        var merchant2 = new Merchant { Id = 2, Name = "Target" };
+        context.Merchants.AddRange(merchant1, merchant2);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.UpdateMerchantAsync(1, "Target");
+
+        // Assert
+        Assert.False(result.Success);
+        Assert.Contains("already exists", result.Message);
+    }
+
+    [Fact]
+    public async Task DeleteMerchantAsync_SuccessfullyDeletes()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new MerchantService(context);
+
+        var merchant = new Merchant { Id = 1, Name = "Walmart" };
+        context.Merchants.Add(merchant);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.DeleteMerchantAsync(1);
+
+        // Assert
+        Assert.True(result.Success);
+        Assert.Empty(context.Merchants);
+    }
+
+    [Fact]
+    public async Task DeleteMerchantAsync_ReportsTransactionAndMappingCounts()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new MerchantService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var merchant = new Merchant { Id = 1, Name = "Walmart" };
+        context.Merchants.Add(merchant);
+
+        var transaction = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            MerchantId = 1
+        };
+        context.Transactions.Add(transaction);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.DeleteMerchantAsync(1);
+
+        // Assert
+        Assert.True(result.Success);
+        Assert.Equal(1, result.TransactionCount);
+        Assert.Contains("1 transaction", result.Message);
+    }
+}
diff --git a/MoneyMap.Tests/Services/ReceiptMatchingServiceTests.cs b/MoneyMap.Tests/Services/ReceiptMatchingServiceTests.cs
new file mode 100644
index 0000000..9b74428
--- /dev/null
+++ b/MoneyMap.Tests/Services/ReceiptMatchingServiceTests.cs
@@ -0,0 +1,330 @@
+using MoneyMap.Models;
+using MoneyMap.Services;
+using MoneyMap.Tests.TestHelpers;
+using Xunit;
+
+namespace MoneyMap.Tests.Services;
+
+public class ReceiptMatchingServiceTests
+{
+    [Fact]
+    public async Task GetTransactionIdsWithReceiptsAsync_ReturnsTransactionIds()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new ReceiptMatchingService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var transaction1 = new Transaction
+        {
+            Id = 1,
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Store A",
+            Memo = "Test",
+            AccountId = 1
+        };
+        var transaction2 = new Transaction
+        {
+            Id = 2,
+            Date = DateTime.Now,
+            Amount = -30.00m,
+            Name = "Store B",
+            Memo = "Test",
+            AccountId = 1
+        };
+        context.Transactions.AddRange(transaction1, transaction2);
+
+        var receipt = new Receipt
+        {
+            Id = 1,
+            TransactionId = 1,
+            FileName = "receipt.pdf",
+            ContentType = "application/pdf",
+            StoragePath = "/receipts/receipt.pdf",
+            FileSizeBytes = 1024,
+            FileHashSha256 = "hash123",
+            UploadedAtUtc = DateTime.UtcNow
+        };
+        context.Receipts.Add(receipt);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.GetTransactionIdsWithReceiptsAsync();
+
+        // Assert
+        Assert.Single(result);
+        Assert.Contains(1L, result);
+        Assert.DoesNotContain(2L, result);
+    }
+
+    [Fact]
+    public async Task FindMatchingTransactionsAsync_FiltersByDateRange()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new ReceiptMatchingService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var receiptDate = new DateTime(2025, 1, 15);
+
+        var withinRange = new Transaction
+        {
+            Id = 1,
+            Date = receiptDate.AddDays(2), // Within +/- 3 days
+            Amount = -50.00m,
+            Name = "Store A",
+            Memo = "Test",
+            AccountId = 1
+        };
+        var outsideRange = new Transaction
+        {
+            Id = 2,
+            Date = receiptDate.AddDays(5), // Outside +/- 3 days
+            Amount = -50.00m,
+            Name = "Store B",
+            Memo = "Test",
+            AccountId = 1
+        };
+        context.Transactions.AddRange(withinRange, outsideRange);
+        await context.SaveChangesAsync();
+
+        var criteria = new ReceiptMatchCriteria
+        {
+            ReceiptDate = receiptDate,
+            ExcludeTransactionIds = new HashSet<long>()
+        };
+
+        // Act
+        var result = await service.FindMatchingTransactionsAsync(criteria);
+
+        // Assert
+        Assert.Single(result);
+        Assert.Equal(1, result[0].Id);
+    }
+
+    [Fact]
+    public async Task FindMatchingTransactionsAsync_FiltersByAmountTolerance()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new ReceiptMatchingService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var receiptDate = DateTime.Now;
+        var receiptTotal = 100.00m;
+
+        var withinTolerance = new Transaction
+        {
+            Id = 1,
+            Date = receiptDate,
+            Amount = -105.00m, // Within 10% tolerance
+            Name = "Store A",
+            Memo = "Test",
+            AccountId = 1
+        };
+        var outsideTolerance = new Transaction
+        {
+            Id = 2,
+            Date = receiptDate,
+            Amount = -150.00m, // Outside 10% tolerance
+            Name = "Store B",
+            Memo = "Test",
+            AccountId = 1
+        };
+        context.Transactions.AddRange(withinTolerance, outsideTolerance);
+        await context.SaveChangesAsync();
+
+        var criteria = new ReceiptMatchCriteria
+        {
+            ReceiptDate = receiptDate,
+            Total = receiptTotal,
+            ExcludeTransactionIds = new HashSet<long>()
+        };
+
+        // Act
+        var result = await service.FindMatchingTransactionsAsync(criteria);
+
+        // Assert
+        Assert.Single(result);
+        Assert.Equal(1, result[0].Id);
+        Assert.True(result[0].IsCloseAmount);
+    }
+
+    [Fact]
+    public async Task FindMatchingTransactionsAsync_MarksExactAmountMatch()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new ReceiptMatchingService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var receiptDate = DateTime.Now;
+        var receiptTotal = 100.00m;
+
+        var exactMatch = new Transaction
+        {
+            Id = 1,
+            Date = receiptDate,
+            Amount = -100.00m, // Exact match
+            Name = "Store A",
+            Memo = "Test",
+            AccountId = 1
+        };
+        context.Transactions.Add(exactMatch);
+        await context.SaveChangesAsync();
+
+        var criteria = new ReceiptMatchCriteria
+        {
+            ReceiptDate = receiptDate,
+            Total = receiptTotal,
+            ExcludeTransactionIds = new HashSet<long>()
+        };
+
+        // Act
+        var result = await service.FindMatchingTransactionsAsync(criteria);
+
+        // Assert
+        Assert.Single(result);
+        Assert.True(result[0].IsExactAmount);
+        Assert.False(result[0].IsCloseAmount);
+    }
+
+    [Fact]
+    public async Task FindMatchingTransactionsAsync_ExcludesTransactionsWithReceipts()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new ReceiptMatchingService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var receiptDate = DateTime.Now;
+
+        var transaction1 = new Transaction
+        {
+            Id = 1,
+            Date = receiptDate,
+            Amount = -50.00m,
+            Name = "Store A",
+            Memo = "Test",
+            AccountId = 1
+        };
+        var transaction2 = new Transaction
+        {
+            Id = 2,
+            Date = receiptDate,
+            Amount = -50.00m,
+            Name = "Store B",
+            Memo = "Test",
+            AccountId = 1
+        };
+        context.Transactions.AddRange(transaction1, transaction2);
+        await context.SaveChangesAsync();
+
+        var criteria = new ReceiptMatchCriteria
+        {
+            ReceiptDate = receiptDate,
+            ExcludeTransactionIds = new HashSet<long> { 1 } // Exclude transaction 1
+        };
+
+        // Act
+        var result = await service.FindMatchingTransactionsAsync(criteria);
+
+        // Assert
+        Assert.Single(result);
+        Assert.Equal(2, result[0].Id);
+    }
+
+    [Fact]
+    public async Task FindMatchingTransactionsAsync_UsesDueDateForBills()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new ReceiptMatchingService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var receiptDate = new DateTime(2025, 1, 1);
+        var dueDate = new DateTime(2025, 1, 15);
+
+        // Transaction on due date + 3 days (should match for bills)
+        var transaction = new Transaction
+        {
+            Id = 1,
+            Date = dueDate.AddDays(3),
+            Amount = -50.00m,
+            Name = "Utility Company",
+            Memo = "Test",
+            AccountId = 1
+        };
+        context.Transactions.Add(transaction);
+        await context.SaveChangesAsync();
+
+        var criteria = new ReceiptMatchCriteria
+        {
+            ReceiptDate = receiptDate,
+            DueDate = dueDate, // Bill with due date
+            ExcludeTransactionIds = new HashSet<long>()
+        };
+
+        // Act
+        var result = await service.FindMatchingTransactionsAsync(criteria);
+
+        // Assert
+        Assert.Single(result);
+        Assert.Equal(1, result[0].Id);
+    }
+}
diff --git a/MoneyMap.Tests/Services/ReferenceDataServiceTests.cs b/MoneyMap.Tests/Services/ReferenceDataServiceTests.cs
new file mode 100644
index 0000000..22bd9db
--- /dev/null
+++ b/MoneyMap.Tests/Services/ReferenceDataServiceTests.cs
@@ -0,0 +1,221 @@
+using MoneyMap.Models;
+using MoneyMap.Services;
+using MoneyMap.Tests.TestHelpers;
+using Xunit;
+
+namespace MoneyMap.Tests.Services;
+
+public class ReferenceDataServiceTests
+{
+    [Fact]
+    public async Task GetAvailableCategoriesAsync_ReturnsDistinctSortedCategories()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new ReferenceDataService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var transaction1 = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            Category = "Groceries"
+        };
+        var transaction2 = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -30.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            Category = "Gas"
+        };
+        var transaction3 = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -20.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            Category = "Groceries" // Duplicate
+        };
+        context.Transactions.AddRange(transaction1, transaction2, transaction3);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.GetAvailableCategoriesAsync();
+
+        // Assert
+        Assert.Equal(2, result.Count);
+        Assert.Contains("Groceries", result);
+        Assert.Contains("Gas", result);
+        Assert.Equal("Gas", result[0]); // Alphabetically sorted
+        Assert.Equal("Groceries", result[1]);
+    }
+
+    [Fact]
+    public async Task GetAvailableCategoriesAsync_ExcludesEmptyCategories()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new ReferenceDataService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var transaction1 = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            Category = "Groceries"
+        };
+        var transaction2 = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -30.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            Category = "" // Empty
+        };
+        var transaction3 = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -20.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            Category = "  " // Whitespace
+        };
+        context.Transactions.AddRange(transaction1, transaction2, transaction3);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.GetAvailableCategoriesAsync();
+
+        // Assert
+        Assert.Single(result);
+        Assert.Equal("Groceries", result[0]);
+    }
+
+    [Fact]
+    public async Task GetAvailableMerchantsAsync_ReturnsSortedMerchants()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new ReferenceDataService(context);
+
+        var merchant1 = new Merchant { Name = "Walmart" };
+        var merchant2 = new Merchant { Name = "Amazon" };
+        var merchant3 = new Merchant { Name = "Target" };
+        context.Merchants.AddRange(merchant1, merchant2, merchant3);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.GetAvailableMerchantsAsync();
+
+        // Assert
+        Assert.Equal(3, result.Count);
+        Assert.Equal("Amazon", result[0].Name); // Alphabetically sorted
+        Assert.Equal("Target", result[1].Name);
+        Assert.Equal("Walmart", result[2].Name);
+    }
+
+    [Fact]
+    public async Task GetAvailableCardsAsync_ReturnsSortedCards()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new ReferenceDataService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var card1 = new Card
+        {
+            AccountId = 1,
+            Issuer = "VISA",
+            Last4 = "3333",
+            Owner = "Bob"
+        };
+        var card2 = new Card
+        {
+            AccountId = 1,
+            Issuer = "Mastercard",
+            Last4 = "1111",
+            Owner = "Alice"
+        };
+        context.Cards.AddRange(card1, card2);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.GetAvailableCardsAsync();
+
+        // Assert
+        Assert.Equal(2, result.Count);
+        Assert.Equal("Alice", result[0].Owner); // Sorted by owner
+        Assert.Equal("Bob", result[1].Owner);
+    }
+
+    [Fact]
+    public async Task GetAvailableAccountsAsync_ReturnsSortedAccounts()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new ReferenceDataService(context);
+
+        var account1 = new Account
+        {
+            Institution = "Wells Fargo",
+            AccountType = AccountType.Checking,
+            Last4 = "5678",
+            Owner = "Test"
+        };
+        var account2 = new Account
+        {
+            Institution = "Bank of America",
+            AccountType = AccountType.Savings,
+            Last4 = "1234",
+            Owner = "Test"
+        };
+        context.Accounts.AddRange(account1, account2);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.GetAvailableAccountsAsync();
+
+        // Assert
+        Assert.Equal(2, result.Count);
+        Assert.Equal("Bank of America", result[0].Institution); // Sorted by institution
+        Assert.Equal("Wells Fargo", result[1].Institution);
+    }
+}
diff --git a/MoneyMap.Tests/Services/TransactionServiceTests.cs b/MoneyMap.Tests/Services/TransactionServiceTests.cs
new file mode 100644
index 0000000..1ad8e2e
--- /dev/null
+++ b/MoneyMap.Tests/Services/TransactionServiceTests.cs
@@ -0,0 +1,229 @@
+using MoneyMap.Models;
+using MoneyMap.Services;
+using MoneyMap.Tests.TestHelpers;
+using Xunit;
+
+namespace MoneyMap.Tests.Services;
+
+public class TransactionServiceTests
+{
+    [Fact]
+    public async Task IsDuplicateAsync_ReturnsFalse_WhenTransactionDoesNotExist()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new TransactionService(context);
+
+        var transaction = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test Store",
+            Memo = "Test purchase",
+            AccountId = 1,
+            CardId = 1
+        };
+
+        // Act
+        var result = await service.IsDuplicateAsync(transaction);
+
+        // Assert
+        Assert.False(result);
+    }
+
+    [Fact]
+    public async Task IsDuplicateAsync_ReturnsTrue_WhenExactDuplicateExists()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new TransactionService(context);
+
+        // Add an account first (required for transaction)
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var existingTransaction = new Transaction
+        {
+            Date = new DateTime(2025, 1, 15),
+            Amount = -50.00m,
+            Name = "Test Store",
+            Memo = "Test purchase",
+            AccountId = 1,
+            CardId = 1
+        };
+        context.Transactions.Add(existingTransaction);
+        await context.SaveChangesAsync();
+
+        var duplicateTransaction = new Transaction
+        {
+            Date = new DateTime(2025, 1, 15),
+            Amount = -50.00m,
+            Name = "Test Store",
+            Memo = "Test purchase",
+            AccountId = 1,
+            CardId = 1
+        };
+
+        // Act
+        var result = await service.IsDuplicateAsync(duplicateTransaction);
+
+        // Assert
+        Assert.True(result);
+    }
+
+    [Fact]
+    public async Task IsDuplicateAsync_ReturnsFalse_WhenAmountDiffers()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new TransactionService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var existingTransaction = new Transaction
+        {
+            Date = new DateTime(2025, 1, 15),
+            Amount = -50.00m,
+            Name = "Test Store",
+            Memo = "Test purchase",
+            AccountId = 1,
+            CardId = 1
+        };
+        context.Transactions.Add(existingTransaction);
+        await context.SaveChangesAsync();
+
+        var differentTransaction = new Transaction
+        {
+            Date = new DateTime(2025, 1, 15),
+            Amount = -51.00m, // Different amount
+            Name = "Test Store",
+            Memo = "Test purchase",
+            AccountId = 1,
+            CardId = 1
+        };
+
+        // Act
+        var result = await service.IsDuplicateAsync(differentTransaction);
+
+        // Assert
+        Assert.False(result);
+    }
+
+    [Fact]
+    public async Task GetTransactionByIdAsync_ReturnsNull_WhenTransactionDoesNotExist()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new TransactionService(context);
+
+        // Act
+        var result = await service.GetTransactionByIdAsync(999);
+
+        // Assert
+        Assert.Null(result);
+    }
+
+    [Fact]
+    public async Task GetTransactionByIdAsync_ReturnsTransaction_WhenExists()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new TransactionService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var transaction = new Transaction
+        {
+            Id = 1,
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test Store",
+            Memo = "Test purchase",
+            AccountId = 1
+        };
+        context.Transactions.Add(transaction);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.GetTransactionByIdAsync(1);
+
+        // Assert
+        Assert.NotNull(result);
+        Assert.Equal("Test Store", result.Name);
+        Assert.Equal(-50.00m, result.Amount);
+    }
+
+    [Fact]
+    public async Task DeleteTransactionAsync_ReturnsTrue_WhenTransactionExists()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new TransactionService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var transaction = new Transaction
+        {
+            Id = 1,
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test Store",
+            Memo = "Test purchase",
+            AccountId = 1
+        };
+        context.Transactions.Add(transaction);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.DeleteTransactionAsync(1);
+
+        // Assert
+        Assert.True(result);
+        Assert.Empty(context.Transactions);
+    }
+
+    [Fact]
+    public async Task DeleteTransactionAsync_ReturnsFalse_WhenTransactionDoesNotExist()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new TransactionService(context);
+
+        // Act
+        var result = await service.DeleteTransactionAsync(999);
+
+        // Assert
+        Assert.False(result);
+    }
+}
diff --git a/MoneyMap.Tests/Services/TransactionStatisticsServiceTests.cs b/MoneyMap.Tests/Services/TransactionStatisticsServiceTests.cs
new file mode 100644
index 0000000..68d13db
--- /dev/null
+++ b/MoneyMap.Tests/Services/TransactionStatisticsServiceTests.cs
@@ -0,0 +1,188 @@
+using MoneyMap.Models;
+using MoneyMap.Services;
+using MoneyMap.Tests.TestHelpers;
+using Xunit;
+
+namespace MoneyMap.Tests.Services;
+
+public class TransactionStatisticsServiceTests
+{
+    [Fact]
+    public async Task CalculateStatsAsync_ReturnsCorrectStatistics()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new TransactionStatisticsService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var debit1 = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Store A",
+            Memo = "Purchase",
+            AccountId = 1
+        };
+        var debit2 = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -30.00m,
+            Name = "Store B",
+            Memo = "Purchase",
+            AccountId = 1
+        };
+        var credit = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = 100.00m,
+            Name = "Deposit",
+            Memo = "Paycheck",
+            AccountId = 1
+        };
+        context.Transactions.AddRange(debit1, debit2, credit);
+        await context.SaveChangesAsync();
+
+        var query = context.Transactions.AsQueryable();
+
+        // Act
+        var result = await service.CalculateStatsAsync(query);
+
+        // Assert
+        Assert.Equal(3, result.Count);
+        Assert.Equal(-80.00m, result.TotalDebits);
+        Assert.Equal(100.00m, result.TotalCredits);
+        Assert.Equal(20.00m, result.NetAmount);
+    }
+
+    [Fact]
+    public async Task GetCategorizationStatsAsync_ReturnsCorrectCounts()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new TransactionStatisticsService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var categorized1 = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            Category = "Groceries"
+        };
+        var categorized2 = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -30.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            Category = "Gas"
+        };
+        var uncategorized = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -20.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            Category = ""
+        };
+        context.Transactions.AddRange(categorized1, categorized2, uncategorized);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.GetCategorizationStatsAsync();
+
+        // Assert
+        Assert.Equal(3, result.TotalTransactions);
+        Assert.Equal(2, result.Categorized);
+        Assert.Equal(1, result.Uncategorized);
+    }
+
+    [Fact]
+    public async Task GetCardStatsForAccountAsync_ReturnsStatsForLinkedCards()
+    {
+        // Arrange
+        using var context = DbContextHelper.CreateInMemoryContext();
+        var service = new TransactionStatisticsService(context);
+
+        var account = new Account
+        {
+            Id = 1,
+            Institution = "Test Bank",
+            AccountType = AccountType.Checking,
+            Last4 = "1234",
+            Owner = "Test Owner"
+        };
+        context.Accounts.Add(account);
+
+        var card1 = new Card
+        {
+            Id = 1,
+            AccountId = 1,
+            Issuer = "VISA",
+            Last4 = "1111",
+            Owner = "Test"
+        };
+        var card2 = new Card
+        {
+            Id = 2,
+            AccountId = 1,
+            Issuer = "Mastercard",
+            Last4 = "2222",
+            Owner = "Test"
+        };
+        context.Cards.AddRange(card1, card2);
+
+        var transaction1 = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -50.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            CardId = 1
+        };
+        var transaction2 = new Transaction
+        {
+            Date = DateTime.Now,
+            Amount = -30.00m,
+            Name = "Test",
+            Memo = "Test",
+            AccountId = 1,
+            CardId = 1
+        };
+        context.Transactions.AddRange(transaction1, transaction2);
+        await context.SaveChangesAsync();
+
+        // Act
+        var result = await service.GetCardStatsForAccountAsync(1);
+
+        // Assert
+        Assert.Equal(2, result.Count);
+        var card1Stats = result.First(c => c.Card.Id == 1);
+        Assert.Equal(2, card1Stats.TransactionCount);
+        var card2Stats = result.First(c => c.Card.Id == 2);
+        Assert.Equal(0, card2Stats.TransactionCount);
+    }
+}
diff --git a/MoneyMap.Tests/TestHelpers/DbContextHelper.cs b/MoneyMap.Tests/TestHelpers/DbContextHelper.cs
new file mode 100644
index 0000000..780d34f
--- /dev/null
+++ b/MoneyMap.Tests/TestHelpers/DbContextHelper.cs
@@ -0,0 +1,20 @@
+using Microsoft.EntityFrameworkCore;
+using MoneyMap.Data;
+
+namespace MoneyMap.Tests.TestHelpers;
+
+public static class DbContextHelper
+{
+    /// <summary>
+    /// Creates an in-memory database context for testing.
+    /// Each call creates a unique database to ensure test isolation.
+    /// </summary>
+    public static MoneyMapContext CreateInMemoryContext()
+    {
+        var options = new DbContextOptionsBuilder<MoneyMapContext>()
+            .UseInMemoryDatabase(databaseName: Guid.NewGuid().ToString())
+            .Options;
+
+        return new MoneyMapContext(options);
+    }
+}
diff --git a/MoneyMap.sln b/MoneyMap.sln
index 8576927..a914c76 100644
--- a/MoneyMap.sln
+++ b/MoneyMap.sln
@@ -5,6 +5,8 @@ VisualStudioVersion = 17.14.36429.23
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MoneyMap", "MoneyMap\MoneyMap.csproj", "{B273A467-3592-4675-B1EC-C41C9CE455DB}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MoneyMap.Tests", "MoneyMap.Tests\MoneyMap.Tests.csproj", "{4CAD4283-4E2D-B998-4839-03B72BDDBEF5}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -15,6 +17,10 @@ Global
 		{B273A467-3592-4675-B1EC-C41C9CE455DB}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{B273A467-3592-4675-B1EC-C41C9CE455DB}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{B273A467-3592-4675-B1EC-C41C9CE455DB}.Release|Any CPU.Build.0 = Release|Any CPU
+		{4CAD4283-4E2D-B998-4839-03B72BDDBEF5}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{4CAD4283-4E2D-B998-4839-03B72BDDBEF5}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{4CAD4283-4E2D-B998-4839-03B72BDDBEF5}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{4CAD4283-4E2D-B998-4839-03B72BDDBEF5}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE