This PR creates a comprehensive integration test project for the NetEvolve.CodeBuilder library following the established folder structure and testing conventions.

Project Structure

The new NetEvolve.CodeBuilder.Tests.Integration project is created under tests/ following the folder structure decision (2025-07-10-folder-structure-and-naming-conventions.md):

tests/
├── NetEvolve.CodeBuilder.Tests.Unit/         # Existing unit tests
└── NetEvolve.CodeBuilder.Tests.Integration/  # New integration tests
    ├── CSharpCodeBuilderIntegrationTests.cs
    ├── CSharpCodeBuilderIntegrationTests.ComplexGeneration.cs
    ├── CSharpCodeBuilderIntegrationTests.ConditionalGeneration.cs
    ├── CSharpCodeBuilderIntegrationTests.Formatting.cs
    ├── CSharpCodeBuilderIntegrationTests.SnapshotTests.cs
    ├── README.md
    └── NetEvolve.CodeBuilder.Tests.Integration.csproj

Test Framework & Dependencies

The project uses:

• TUnit as the primary testing framework
• Verify.TUnit for snapshot testing capabilities
• NetEvolve.Extensions.TUnit with IntegrationTestAttribute
• Microsoft.Testing.Extensions.CodeCoverage for coverage reporting

Integration Test Coverage

The integration tests validate end-to-end scenarios including:

Complex Code Generation

• Complete C# class generation with XML documentation
• Interface generation with async methods
• Proper namespace and using statement handling

Conditional Content Generation

• Dynamic method generation using AppendIf patterns
• Reflection-based property generation
• Template-driven code creation

Formatting & Indentation

• Space-based indentation (4 spaces per level)
• Tab-based indentation validation
• Nested code block formatting
• Enum generation with attributes

Example Test

[Test]
public async Task GenerateCompleteClass_Should_ProduceCorrectOutput()
{
    var builder = new CSharpCodeBuilder();
    
    builder
        .AppendLine("using System;")
        .AppendLine("namespace MyApplication.Models")
        .Append("{")
        .AppendLine("public class Customer")
        .Append("{")
        .AppendLine("public string Id { get; set; }")
        .Append("}")
        .Append("}");
    
    var result = builder.ToString();
    
    _ = await Assert.That(result).Contains("namespace MyApplication.Models");
    _ = await Assert.That(result).Contains("    public class Customer");
    _ = await Assert.That(result).Contains("        public string Id { get; set; }");
}

Key Features

• No Mocking: All tests use real CSharpCodeBuilder instances
• End-to-End Validation: Tests verify both content and formatting
• Real-World Scenarios: Covers actual code generation use cases
• Snapshot Testing Ready: Infrastructure prepared for Verify.TUnit snapshot tests
• Comprehensive Documentation: Includes README with usage examples

All 7 integration tests pass successfully, validating the complete functionality of the CodeBuilder library's code generation capabilities.

Fixes #12.

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