Added payment gateway ledger service to payments feature

LiteCharms.Features.MidrandBooks.Tests/Common/Fixture.cs

@@ -24,7 +24,8 @@ public class Fixture : IDisposable
             .AddEnvironmentVariables()
             .Build();
 
-        Services = new ServiceCollection()            
+        Services = new ServiceCollection()
+            .AddHttpClient()
             .AddMediator()
             .AddLogging()
             .AddEmailServiceBus()
@@ -33,6 +34,7 @@ public class Fixture : IDisposable
             .AddEmailServices(Configuration)
             .AddSingleton(Configuration)
             .AddShopServices()
+            .AddHashServices(Configuration)
             .BuildServiceProvider();
 
         Mediator = Services.GetRequiredService<IMediator>();

LiteCharms.Features.MidrandBooks.Tests/LiteCharms.Features.MidrandBooks.Tests.csproj

@@ -39,6 +39,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <Using Include="System.Net" />
     <Using Include="System.Text.Json" />
     <Using Include="System.Diagnostics" />
     <Using Include="Xunit" />

LiteCharms.Features.MidrandBooks.Tests/PayfastServiceFeatureTests.cs

@@ -0,0 +1,113 @@
+using LiteCharms.Features.MidrandBooks.Payments;
+using LiteCharms.Features.MidrandBooks.Payments.Models;
+using LiteCharms.Features.MidrandBooks.Tests.Common;
+
+namespace LiteCharms.Features.MidrandBooks.Tests;
+
+public sealed class PayfastServiceFeatureTests(Fixture fixture) : IClassFixture<Fixture>
+{
+    private readonly PayfastService payfastService = fixture.Services.GetRequiredService<PayfastService>();
+
+    [IntegrationFact]
+    public async Task WriteLedgerEntryAsync_ShouldReturn_ResultWithGatewayLedgerId()
+    {
+        var request = new CreateGatewayLedgerEntry
+        {
+            OrderId = 1,
+            PaymentId = 1,
+            MerchantPaymentId = "M_REF_TEST_99",
+            PayfastPaymentId = "PF_SYS_ID_10023",
+            CustomerEmail = "buyer@litecharms.co.za",
+            AmountGross = 350.00m,
+            AmountFee = 12.50m,
+            AmountNet = 337.50m,
+            PaymentStatus = "COMPLETE"
+        };
+
+        var result = await payfastService.WriteLedgerEntryAsync(request, fixture.CancellationToken);
+
+        Assert.True(result.IsSuccess);
+        Assert.True(result.Value > 0);
+    }
+
+    [IntegrationFact]
+    public async Task ValidateReferrerIpAsync_WithValidPayfastHostIp_ShouldReturnTrue()
+    {
+        var addresses = await Dns.GetHostAddressesAsync("sandbox.payfast.co.za", fixture.CancellationToken);
+
+        string liveTargetIp = addresses.First().ToString();
+
+        var result = await payfastService.ValidateReferrerIpAsync(liveTargetIp, fixture.CancellationToken);
+
+        Assert.True(result.IsSuccess);
+        Assert.True(result.Value);
+    }
+
+    [IntegrationFact]
+    public async Task ValidateReferrerIpAsync_WithUntrustedIp_ShouldReturnFalse()
+    {
+        string rogueIp = "8.8.8.8";
+
+        var result = await payfastService.ValidateReferrerIpAsync(rogueIp, fixture.CancellationToken);
+
+        Assert.True(result.IsSuccess);
+        Assert.False(result.Value);
+    }
+
+    [IntegrationFact]
+    public void ValidatePaymentAmount_WhenWithinAllowableDelta_ShouldReturnTrue()
+    {
+        decimal systemExpectedTotal = 199.99m;
+        string gatewayClearedGross = "200.00"; // Variance is exactly R0.01
+
+        var result = payfastService.ValidatePaymentAmount(systemExpectedTotal, gatewayClearedGross);
+
+        Assert.True(result.IsSuccess);
+        Assert.True(result.Value);
+    }
+
+    [IntegrationFact]
+    public void ValidatePaymentAmount_WhenVarianceBreachesDeltaBounds_ShouldReturnFalse()
+    {
+        decimal systemExpectedTotal = 199.99m;
+        string gatewayClearedGross = "150.00";
+
+        var result = payfastService.ValidatePaymentAmount(systemExpectedTotal, gatewayClearedGross);
+
+        Assert.True(result.IsSuccess);
+        Assert.False(result.Value);
+    }
+
+    [IntegrationFact]
+    public async Task ValidateServerConfirmationAsync_WithUnrecognizedPayload_ShouldReturnFalseFromCentralGateway()
+    {
+        // Arrange - Execute against actual Payfast servers using raw mock parameters. 
+        // The server handshake will return 200 OK with string payload 'INVALID'
+        string arbitraryParameters = "merchant_id=10000000&payment_status=COMPLETE";
+
+        var result = await payfastService.ValidateServerConfirmationAsync(arbitraryParameters, isSandbox: true, fixture.CancellationToken);
+
+        Assert.True(result.IsSuccess); 
+        Assert.False(result.Value);   // Handshake data rejected as fraudulent/unrecognized
+    }
+
+    [IntegrationFact]
+    public void GenerateSignature_WithStandardTelemetryData_ShouldSucceedAndHashString()
+    {
+        var telemetryPayload = new Dictionary<string, string?>
+        {
+            { "merchant_id", "10049307" },
+            { "merchant_key", "ju6navn0jcbf0" },
+            { "amount_gross", "250.00" },
+            { "item_name", "Midrand School Textbook Variant A" }
+        };
+
+        string passphrase = "oauth_test_signature_pass";
+
+        var result = PayfastService.GenerateSignature(telemetryPayload, passphrase);
+
+        Assert.True(result.IsSuccess);
+        Assert.False(string.IsNullOrWhiteSpace(result.Value));
+        Assert.Equal(32, result.Value.Length); // MD5 outputs hex representations totaling 32 characters
+    }
+}

LiteCharms.Features.MidrandBooks.Tests/appsettings.json

@@ -1,4 +1,16 @@
 {
+  "ValidPayfastHosts": [
+    "www.payfast.co.za",
+    "sandbox.payfast.co.za",
+    "w1w.payfast.co.za",
+    "w2w.payfast.co.za",
+    "ips.payfast.co.za",
+    "api.payfast.co.za",
+    "payment.payfast.io"
+  ],
+  "HasherSettings": {
+    "MinHashLength": 11
+  },
   "BookshopS3Settings": {
     "ServiceUrl": "http://192.168.1.177:30900",
     "Region": "garage",