Initial commit

.gitignore

+# ==================================
+# Visual Studio & .NET Ignore File
+# ==================================
+
+# 1. Build results (These are generated automatically when building, do not push them!)
+[Dd]ebug/
+[Dd]ebugPublic/
+[Rr]elease/
+[Rr]eleases/
+x64/
+x86/
+[Ww][Ii][Nn]32/
+[Aa][Rr][Mm]/
+[Aa][Rr][Mm]64/
+bld/
+[Bb]in/
+[Oo]bj/
+[Ll]og/
+[Ll]ogs/
+
+# 2. Visual Studio user-specific files (Local settings for your specific computer)
+.vs/
+*.user
+*.userosscache
+*.sln.docstates
+*.suo
+*.userprefs
+*.vssscc
+
+# 3. Test results (Don't push test outputs, the CI/CD pipeline will generate its own)
+[Tt]est[Rr]esult*/
+[Bb]uild[Ll]og.*
+*.trx
+*.testsettings
+
+# 4. Environment variables and secrets (Security best practice)
+.env
+appsettings.Development.json
\ No newline at end of file

.gitlab-ci.yml

+# 1. Specify the environment 
+# We use the official Microsoft .NET 8 SDK image to run our commands
+image: mcr.microsoft.com/dotnet/sdk:8.0
+
+# 2. Define the stages of the pipeline
+# These run in order: first build, then test.
+stages:
+  - build
+  - test
+
+# 3. The Build Job
+# This ensures the code actually compiles before we even try to test it
+build_project:
+  stage: build
+  script:
+    - echo "Building the ASP.NET Core 8 Solution..."
+    - dotnet build ECommerceApp.Solution.sln --configuration Release
+  
+# 4. The Test Job
+# This runs the xUnit unit and integration tests we created
+run_tests:
+  stage: test
+  script:
+    - echo "Running xUnit Tests..."
+    - dotnet test ECommerceApp.Solution.sln --configuration Release --logger "console;verbosity=detailed"
+  # Optional: This tells the pipeline to stop if the tests fail
+  allow_failure: false
\ No newline at end of file

ECommerceApp.Tests/ECommerceApp.Tests.csproj

+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
+    <PackageReference Include="Moq" Version="4.20.72" />
+    <PackageReference Include="xunit" Version="2.5.3" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.3" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\ECommerceApp\ECommerceApp.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Xunit" />
+  </ItemGroup>
+
+</Project>

ECommerceApp.Tests/IntegrationTests/OrderCheckoutServiceIntegrationTests.cs

+using ECommerceApp.Models;
+using ECommerceApp.Services;
+using Moq;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ECommerceApp.Tests.IntegrationTests
+{
+    public class OrderCheckoutServiceIntegrationTests
+    {
+        [Fact]
+        public async Task ProcessOrderAsync_IntegratesWithDatabaseService_AssignsId()
+        {
+            // 1. ARRANGE
+            // We use the ACTUAL FakeDatabaseService, not a Moq object
+            var realFakeDbService = new FakeDatabaseService();
+
+            // We inject the actual service into the checkout service
+            var checkoutService = new OrderCheckoutService(realFakeDbService);
+
+            // 2. ACT
+            // This will take at least 500ms because it is running the actual Task.Delay
+            var result = await checkoutService.ProcessOrderAsync(50m, "WINTER20");
+
+            // 3. ASSERT
+            Assert.Equal(40m, result.FinalTotal); // 50 - 20% = 40
+
+            // The crucial integration check: Did the database service successfully 
+            // process the order and attach the simulated database ID (999)?
+            Assert.Equal(999, result.Id);
+        }
+    }
+}

ECommerceApp.Tests/UnitTests/OrderCheckoutServiceUnitTests.cs

+using ECommerceApp.Models;
+using ECommerceApp.Services;
+using Moq;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ECommerceApp.Tests.UnitTests
+{
+    public class OrderCheckoutServiceUnitTests
+    {
+        [Fact]
+        public async Task ProcessOrderAsync_WithSummer10Code_Applies10PercentDiscount()
+        {
+            // 1. ARRANGE (Set up the test)
+            // We create a mock (a fake version) of the IDatabaseService
+            var mockDbService = new Mock<IDatabaseService>();
+
+            // We tell the mock to just return a dummy ID immediately if called
+            mockDbService
+                .Setup(db => db.SaveOrderAsync(It.IsAny<Order>()))
+                .ReturnsAsync(1);
+
+            // We inject the mock into our service
+            var checkoutService = new OrderCheckoutService(mockDbService.Object);
+
+            // 2. ACT (Run the method being tested)
+            var result = await checkoutService.ProcessOrderAsync(100m, "SUMMER10");
+
+            // 3. ASSERT (Verify the results)
+            Assert.Equal(90m, result.FinalTotal); // 100 - 10% = 90
+            Assert.Equal("SUMMER10", result.DiscountCode);
+
+            // Verify that the service actually tried to save the order once
+            mockDbService.Verify(db => db.SaveOrderAsync(It.IsAny<Order>()), Times.Once);
+        }
+
+        [Fact]
+        public async Task ProcessOrderAsync_WithNoCode_AppliesZeroDiscount()
+        {
+            // 1. ARRANGE
+            var mockDbService = new Mock<IDatabaseService>();
+            var checkoutService = new OrderCheckoutService(mockDbService.Object);
+
+            // 2. ACT
+            var result = await checkoutService.ProcessOrderAsync(100m, null);
+
+            // 3. ASSERT
+            Assert.Equal(100m, result.FinalTotal); // No discount
+        }
+    }
+}

ECommerceApp.sln

+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.11.35312.102
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ECommerceApp", "ECommerceApp\ECommerceApp.csproj", "{9A58B8CD-F227-46E6-AF2A-3A08754576D2}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ECommerceApp.Tests", "ECommerceApp.Tests\ECommerceApp.Tests.csproj", "{97B94E99-3794-4F3D-B200-5CCEE500B7F0}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{9A58B8CD-F227-46E6-AF2A-3A08754576D2}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{9A58B8CD-F227-46E6-AF2A-3A08754576D2}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{9A58B8CD-F227-46E6-AF2A-3A08754576D2}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{9A58B8CD-F227-46E6-AF2A-3A08754576D2}.Release|Any CPU.Build.0 = Release|Any CPU
+		{97B94E99-3794-4F3D-B200-5CCEE500B7F0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{97B94E99-3794-4F3D-B200-5CCEE500B7F0}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{97B94E99-3794-4F3D-B200-5CCEE500B7F0}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{97B94E99-3794-4F3D-B200-5CCEE500B7F0}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {6D8CBDE1-39D9-4891-B63A-432E606E43E6}
+	EndGlobalSection
+EndGlobal

ECommerceApp/Controllers/WeatherForecastController.cs

+using Microsoft.AspNetCore.Mvc;
+
+namespace ECommerceApp.Controllers
+{
+    [ApiController]
+    [Route("[controller]")]
+    public class WeatherForecastController : ControllerBase
+    {
+        private static readonly string[] Summaries = new[]
+        {
+            "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
+        };
+
+        private readonly ILogger<WeatherForecastController> _logger;
+
+        public WeatherForecastController(ILogger<WeatherForecastController> logger)
+        {
+            _logger = logger;
+        }
+
+        [HttpGet(Name = "GetWeatherForecast")]
+        public IEnumerable<WeatherForecast> Get()
+        {
+            return Enumerable.Range(1, 5).Select(index => new WeatherForecast
+            {
+                Date = DateOnly.FromDateTime(DateTime.Now.AddDays(index)),
+                TemperatureC = Random.Shared.Next(-20, 55),
+                Summary = Summaries[Random.Shared.Next(Summaries.Length)]
+            })
+            .ToArray();
+        }
+    }
+}

ECommerceApp/ECommerceApp.csproj

+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.4.0" />
+  </ItemGroup>
+
+</Project>

ECommerceApp/ECommerceApp.http

+@ECommerceApp_HostAddress = http://localhost:5241
+
+GET {{ECommerceApp_HostAddress}}/weatherforecast/
+Accept: application/json
+
+###

ECommerceApp/Models/Order.cs

+namespace ECommerceApp.Models
+{
+    public class Order
+    {
+        public int Id { get; set; }
+        public decimal SubTotal { get; set; }
+        public string? DiscountCode { get; set; }
+        public decimal FinalTotal { get; set; }
+    }
+}

ECommerceApp/Program.cs

+using ECommerceApp.Services;
+
+var builder = WebApplication.CreateBuilder(args);
+
+// Add services to the container.
+
+builder.Services.AddControllers();
+// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
+builder.Services.AddEndpointsApiExplorer();
+builder.Services.AddSwaggerGen();
+builder.Services.AddScoped<UserRegistrationService>();
+var app = builder.Build();
+
+app.MapGet("/test-registration", (string email, UserRegistrationService registrationService) =>
+{
+
+    bool isValid = registrationService.ValidateAndRegister(email);
+
+    if (isValid)
+        return Results.Ok($"Success! Check the command prompt for the log.");
+    else
+        return Results.BadRequest($"Failed! Check the command prompt for the warning.");
+});
+// Configure the HTTP request pipeline.
+if (app.Environment.IsDevelopment())
+{
+    app.UseSwagger();
+    app.UseSwaggerUI();
+}
+
+app.UseHttpsRedirection();
+
+app.UseAuthorization();
+
+app.MapControllers();
+
+app.Run();

ECommerceApp/Properties/launchSettings.json

+{
+  "$schema": "http://json.schemastore.org/launchsettings.json",
+  "iisSettings": {
+    "windowsAuthentication": false,
+    "anonymousAuthentication": true,
+    "iisExpress": {
+      "applicationUrl": "http://localhost:52425",
+      "sslPort": 44324
+    }
+  },
+  "profiles": {
+    "http": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": true,
+      "launchUrl": "swagger",
+      "applicationUrl": "http://localhost:5241",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+    "https": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": true,
+      "launchUrl": "swagger",
+      "applicationUrl": "https://localhost:7007;http://localhost:5241",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+    "IIS Express": {
+      "commandName": "IISExpress",
+      "launchBrowser": true,
+      "launchUrl": "swagger",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    }
+  }
+}

ECommerceApp/Services/FakeDatabaseService.cs

+using ECommerceApp.Models;
+
+namespace ECommerceApp.Services
+{
+    public class FakeDatabaseService : IDatabaseService
+    {
+        public async Task<int> SaveOrderAsync(Order order)
+        {
+            // Simulate a 500 millisecond database/network delay
+            await Task.Delay(500);
+
+            // Assign a fake static ID to simulate an auto-incrementing database column
+            order.Id = 999;
+
+            return order.Id;
+        }
+    }
+}

ECommerceApp/Services/IDatabaseService.cs

+using ECommerceApp.Models;
+
+namespace ECommerceApp.Services
+{
+    public interface IDatabaseService
+    {
+        // We use Task to simulate an async database call
+        Task<int> SaveOrderAsync(Order order);
+    }
+}

ECommerceApp/Services/OrderCheckoutService.cs

+using ECommerceApp.Models;
+
+namespace ECommerceApp.Services
+{
+    public class OrderCheckoutService
+    {
+        private readonly IDatabaseService _dbService;
+
+        public OrderCheckoutService(IDatabaseService dbService)
+        {
+            _dbService = dbService;
+        }
+
+        public async Task<Order> ProcessOrderAsync(decimal subTotal, string? discountCode)
+        {
+            var order = new Order
+            {
+                SubTotal = subTotal,
+                DiscountCode = discountCode
+            };
+
+            // 1. Simple internal discount logic
+            decimal discountPercentage = 0;
+
+            if (discountCode == "SUMMER10")
+            {
+                discountPercentage = 10;
+            }
+            else if (discountCode == "WINTER20")
+            {
+                discountPercentage = 20;
+            }
+
+            // 2. Apply math logic
+            decimal discountAmount = subTotal * (discountPercentage / 100m);
+            order.FinalTotal = subTotal - discountAmount;
+
+            // 3. Simulate saving to the database
+            await _dbService.SaveOrderAsync(order);
+
+            return order;
+        }
+    }
+}

ECommerceApp/Services/UserRegistrationService.cs

+namespace ECommerceApp.Services
+{
+    public class UserRegistrationService
+    {
+        // 1. Declare the logger
+        private readonly ILogger<UserRegistrationService> _logger;
+
+        // 2. Inject the logger via constructor
+        public UserRegistrationService(ILogger<UserRegistrationService> logger)
+        {
+            _logger = logger;
+        }
+
+        public bool ValidateAndRegister(string email)
+        {
+            // Log that a process has started (Information)
+            _logger.LogInformation("Attempting to register user with email: {Email} at {Date}", email,DateTime.Now);
+
+            // Simple business logic: Is it a valid email?
+            if (string.IsNullOrWhiteSpace(email) || !email.Contains("@"))
+            {
+                // Log a warning if the user did something wrong (Warning)
+                _logger.LogWarning("Registration failed. Invalid email format provided: {Email} at {Date}", email,DateTime.Now);
+                return false;
+            }
+
+            // Log successful completion (Information)
+            _logger.LogInformation("User {Email} successfully registered.", email);
+
+            return true;
+        }
+    }
+}

ECommerceApp/WeatherForecast.cs

+namespace ECommerceApp
+{
+    public class WeatherForecast
+    {
+        public DateOnly Date { get; set; }
+
+        public int TemperatureC { get; set; }
+
+        public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);
+
+        public string? Summary { get; set; }
+    }
+}

ECommerceApp/appsettings.json

+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  },
+  "AllowedHosts": "*"
+}