Book Image

Hands-On Microservices with Kotlin

By : Juan Antonio Medina Iglesias
Book Image

Hands-On Microservices with Kotlin

By: Juan Antonio Medina Iglesias

Overview of this book

With Google's inclusion of first-class support for Kotlin in their Android ecosystem, Kotlin's future as a mainstream language is assured. Microservices help design scalable, easy-to-maintain web applications; Kotlin allows us to take advantage of modern idioms to simplify our development and create high-quality services. With 100% interoperability with the JVM, Kotlin makes working with existing Java code easier. Well-known Java systems such as Spring, Jackson, and Reactor have included Kotlin modules to exploit its language features. This book guides the reader in designing and implementing services, and producing production-ready, testable, lean code that's shorter and simpler than a traditional Java implementation. Reap the benefits of using the reactive paradigm and take advantage of non-blocking techniques to take your services to the next level in terms of industry standards. You will consume NoSQL databases reactively to allow you to create high-throughput microservices. Create cloud-native microservices that can run on a wide range of cloud providers, and monitor them. You will create Docker containers for your microservices and scale them. Finally, you will deploy your microservices in OpenShift Online.
Table of Contents (14 chapters)

Mocking beans

Testing complex systems can be challenging, especially when we are dealing with dependencies. If our software depends on an external system such as a database or another service backend, it's hard to make our test without predicting the results from something that is not in our control. We can use a mechanism to prevent this from affecting us. We can use mocks that will mimic the expected output from another system.

Making our tests repeatable is a must in modern software development. Mocking will allow us to always get the same result, regardless of how many times, or in what order, our tests run.

Why we mock

Let's go back to our previous test, where we tested our CustomerController in our CustomerControllerTest...