Chapter 10. Testing microservices: Part 2
This chapter covers
- Techniques for testing services in isolation
- Using consumer-driven contract testing to write tests that quickly yet reliably verify interservice communication
- When and how to do end-to-end testing of applications
This chapter builds on the previous chapter, which introduced testing concepts, including the test pyramid. The test pyramid describes the relative proportions of the different types of tests that you should write. The previous chapter described how to write unit tests, which are at the base of the testing pyramid. In this chapter, we continue our ascent of the testing pyramid.
This chapter begins with how to write integration tests, which are the level above unit tests in the testing pyramid. Integration tests verify that a service can properly interact with infrastructure services, such as databases, and other application services. Next, I cover component tests, which are acceptance tests for services. A component test tests a service in isolation by using stubs for its dependencies. After that, I describe how to write end-to-end tests, which test a group of services or the entire application. End-to-end tests are at the top of the test pyramid and should, therefore, be used sparingly.
Let’s start by taking a look at how to write integration tests.