How to detect SOLID principle violations?

1. Single Responsibility (SRP):
   Symptom: Large classes handling multiple tasks.
   Detection: Check for classes with too many responsibilities or methods. Use tools like SonarQube for complexity warnings.

2. Open/Closed (OCP):
   Symptom: Modifying existing classes for new features.
   Detection: Review change logs and check for frequent edits to core classes.

3. Liskov Substitution (LSP):
   Symptom: Subclasses that break functionality when used in place of base classes.
   Detection: Write unit tests that fail when incorrect subclass behavior is introduced.

4. Interface Segregation (ISP):
   Symptom: Classes implementing methods they don't use.
   Detection: Look for bloated interfaces. Check if classes use all implemented methods.

5. Dependency Inversion (DIP):
   Symptom: High coupling between classes.
   Detection: Identify direct dependencies on concrete classes. Use tools like NDepend to detect tight coupling.

💡General Tips: Use code reviews, static analysis tools (SonarQube, NDepend), and automated tests to catch violations.