In the previous chapter, we finished the frontend development. Does it mean we are done with the development? No! Writing tests is also part of development. In this chapter we will discuss what types of testing there are out there, how to do them, and when to use them. In this chapter we will explain the difference between manual testers and automation testers and discuss several testing platforms and frameworks. We hope you enjoy and that by the end of this chapter you know how extremely important that topic is.