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LegacyCodeNightmare - Refactoring Legacy C# Code with Dependency Injection and Testing

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This .NET 7.0 solution demonstrates how to incrementally refactor legacy code by introducing dependency injection, abstractions, and async patterns while maintaining backward compatibility and testability. The project implements a blog fetching and processing system that retrieves HTML content from a URL, saves it locally, processes it, and writes timestamped output files. The code intentionally showcases common legacy anti-patterns alongside their refactored counterparts.

Key refactoring improvements demonstrated include extracting hard-coded HTTP calls into an IHttpClient interface with a HttpClientWrapper implementation, converting synchronous blocking .GetAwaiter().GetResult() calls to proper async/await, and separating file I/O concerns into a dedicated BlogFetcher class. The solution includes an xUnit test project using Moq for mocking the IHttpClient dependency, showing how dependency injection enables testability in previously untestable code.

Getting Started

Prerequisites

  • .NET 7.0 SDK or later

Running the Project

cd LegacyCodeNightmare/LegacyCodeNightmare.SomeLegacyCode
dotnet run

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