Building Event-Driven Microservices, 2nd Edition

Chapter 20. Testing Event-Driven Microservices

The small and purpose-built nature of microservices make them relatively easy to test, particularly in comparison to larger services. Event streams, queues, and request-response APIs provide the inputs. State is localized to the microservice’s own independent state store, and output events are written to its output streams. This chapter covers testing principles and strategies, including unit testing, integration testing, and performance testing.

General Testing Principles

Event-driven microservices share testing best practices common to all applications. Functional testing, such as unit, integration, system, and regression testing, ensures that the microservice does what it is supposed to and that it doesn’t do what it should not do. Nonfunctional testing, such as performance, load, stress, and recovery testing, ensures that it behaves as expected under various environmental scenarios.

Now, before going much further, it’s important to note that this chapter is meant to be a companion to more extensive works on the principles and how-tos of testing. After all, many books, blogs, and documents have been written on testing, and I certainly can’t cover testing to the extent that they do. This chapter primarily looks at testing methodologies specific to event-driven architectures. You’ll need to consult your own sources on language-specific testing frameworks and testing best practices to complement this chapter.

Unit-Testing Microservice ...