NetArchTest: Architectural Testing for .NET Applications

In modern software development, ensuring that an application adheres to its architectural principles is critical for maintaining scalability, reliability, and maintainability. The NetArchTest library offers developers a way to validate architectural rules and enforce best practices in their .NET applications.

In this blog, we will explore what NetArchTest is, its key features, and how you can use it to test and maintain architectural integrity in your .NET projects.

What is NetArchTest?

NetArchTest is a lightweight and intuitive library for .NET that allows developers to test and validate architectural rules in their codebase. Inspired by the popular Java library ArchUnit, NetArchTest provides tools for defining and enforcing dependencies, layering, and other architectural constraints within .NET applications.

It helps developers answer questions like:

• Are layers properly isolated?
• Are certain namespaces or assemblies restricted to specific parts of the codebase?
• Are dependencies following the defined architecture?

Key Features of NetArchTest

1. Layered Architecture Validation

• Enforce constraints between layers, such as ensuring the data access layer does not directly depend on the presentation layer.

2. Dependency Checks

• Validate that only allowed dependencies exist between namespaces, classes, or assemblies.

3. Flexibility with LINQ Syntax

• Write tests using a fluent LINQ-style syntax that makes defining rules straightforward and readable.

4. Integration with Test Frameworks

• Works seamlessly with popular test frameworks like NUnit, MSTest, and xUnit.

5. Lightweight and Easy to Use

• The library has minimal setup requirements and can be quickly integrated into existing projects.

Getting Started with NetArchTest

Here is a step-by-step guide to using NetArchTest in your project:

Step 1: Install the Library

Add NetArchTest to your project via NuGet:

Install-Package NetArchTest        

Step 2: Define Architectural Rules

Create rules based on your application’s architecture. For example, if you want to ensure that classes in the BusinessLogic namespace do not depend on the Presentation namespace:

using NetArchTest.Rules;

[TestClass]
public class ArchitectureTests
{
    [TestMethod]
    public void BusinessLogic_ShouldNotDependOnPresentation()
    {
        var result = Types.InNamespace("MyApp.BusinessLogic")
            .ShouldNot()
            .HaveDependencyOn("MyApp.Presentation")
            .GetResult();

        Assert.IsTrue(result.IsSuccessful, "BusinessLogic layer has a dependency on Presentation layer.");
    }
}        

Step 3: Run the Tests

Execute the tests as part of your CI/CD pipeline or during local development to ensure compliance with architectural rules.

Advanced Scenarios

1. Restricting Access to Specific Assemblies

Prevent certain parts of your application from referencing a third-party library:

[TestMethod]
public void Core_ShouldNotReferenceExternalLibraries()
{
    var result = Types.InNamespace("MyApp.Core")
        .ShouldNot()
        .HaveDependencyOn("ExternalLibrary")
        .GetResult();

    Assert.IsTrue(result.IsSuccessful, "Core has an unwanted dependency on ExternalLibrary.");
}        

2. Validating Class Annotations

Ensure specific classes are marked with required attributes:

[TestMethod]
public void Controllers_ShouldHaveApiControllerAttribute()
{
    var result = Types.InNamespace("MyApp.Controllers")
        .That()
        .ResideInNamespace("MyApp.Controllers")
        .Should()
        .HaveCustomAttribute(typeof(ApiControllerAttribute))
        .GetResult();

    Assert.IsTrue(result.IsSuccessful, "Some controllers are missing the ApiController attribute.");
}        

Best Practices for Using NetArchTest

1. Start Early: Define and enforce architectural rules at the beginning of your project to prevent violations later.
2. Integrate with CI/CD: Ensure architectural tests are part of your automated testing pipeline.
3. Iterate on Rules: Continuously refine rules as your application grows and evolves.
4. Communicate Constraints: Document and share the architectural rules with your team to ensure alignment.

Benefits of NetArchTest

• Improved Code Quality: Enforcing architectural rules reduces technical debt and ensures cleaner code.
• Easier Maintenance: Consistent architecture makes it easier for teams to maintain and extend the application.
• Early Detection of Issues: Architectural problems are identified and resolved during development, preventing costly fixes later.

NetArchTest is a powerful tool for maintaining the architectural integrity of your .NET applications. By defining and enforcing rules, it helps teams adhere to best practices and ensures the codebase remains scalable, maintainable, and aligned with the intended design.

If you’re working on a .NET project and want to safeguard your architecture, NetArchTest is an excellent library to include in your development toolkit. Start using it today to experience the benefits of architectural testing firsthand.

Nadir Riyani holds a Master in Computer Application and brings 15 years of experience in the IT industry to his role as an Engineering Manager. With deep expertise in Microsoft technologies, Splunk, DevOps Automation, Database systems, and Cloud technologies? Nadir is a seasoned professional known for his technical acumen and leadership skills. He has published over 200 articles in public forums, sharing his knowledge and insights with the broader tech community. Nadir's extensive experience and contributions make him a respected figure in the IT world.