Conclusion

The SOLID principles of object-oriented programming are great — tested and tried principles used widely to build flexible, scalable, and maintainable software systems.

In this lesson, you’ve learned:

• The Liskov Substitution Principle.
• The Interface Segregation Principle.
• The Dependency Inversion Principle.

If you want to explore more about SOLID principles, check out the “Architecting for Testing” chapter of Android Test-Driven Development by Tutorials.