ArchUnit

About

ArchUnit is a popular Java library designed to help developers enforce architectural constraints in their codebase. It allows teams to validate architecture rules and prevent the introduction of unwanted dependencies or code patterns. This is especially useful for maintaining consistency, reducing technical debt, and ensuring the system adheres to predefined architectural principles.

Refer to the official documentation for more details - https://github.com/TNG/ArchUnit/tree/main

Key Features of ArchUnit

1. Architecture Rules Validation:

   • Define rules to ensure the codebase complies with architectural decisions.

   • Example: Prevent dependencies from the service package to the controller package.

2. Seamless Integration:

   • Can be easily integrated into JUnit tests.

   • Works seamlessly with build tools like Maven and Gradle.

3. Flexible API:

   • Provides a fluent API style for defining architectural rules in Java.

4. Predefined Rules:

   • Comes with predefined rules for common scenarios, like ensuring classes in a certain package are annotated with specific annotations.

5. Custom Rules:

   • Supports writing custom rules for specific architectural requirements.

Use Cases

1. Layered Architecture Validation:

   • Enforce separation between layers, e.g., controllers should not directly access repositories.

2. Package Dependency Management:

   • Prevent cyclic dependencies between packages.

   • Ensure only approved packages are accessed.

3. Annotation Constraints:

   • Validate that certain annotations are applied to specific classes or methods.

4. Class and Interface Constraints:

   • Ensure specific naming conventions.

   • Validate superclass or interface implementations.

5. Third-Party Dependency Enforcement:

   • Restrict or allow the use of certain libraries in specific packages.

Setting Up ArchUnit in Maven

Add the Dependency: Include ArchUnit in pom.xml

<dependency>
    <groupId>com.tngtech.archunit</groupId>
    <artifactId>archunit</artifactId>
    <version>1.0.0</version>
</dependency>
<dependency>
    <groupId>com.tngtech.archunit</groupId>
    <artifactId>archunit-junit5</artifactId>
</dependency>

Advantages of ArchUnit

1. Proactive Code Quality: Catch architectural violations during development rather than post-deployment.

2. Automated Enforcement: Integrates with CI/CD pipelines to ensure every build complies with architectural rules.

3. Customizable Rules: Developers can tailor rules to match project-specific needs.

4. Ease of Use: Simple to learn and integrate with existing test setups.