Which different types of tests exist for microservices, how can they work for other areas of software, and what are their benefits? Read this post for answers.
Join the DZone community and get the full member experience. Development teams are increasingly choosing a microservices architecture over monolithic structures in order to boost apps’ agility, scalability, and maintainability. With this decision to switch to the modular software architecture — in which each service is a separate unit with its own logic and database that communicates with other units through APIs — comes the need for new testing strategies and new testing tools. Testing microservices is a critical part of the microservices application process: you need to ensure that your code doesn’t break within the unit, that the dependencies in the microservices continue to work (and work quickly), and that your APIs meet the defined contracts. Yet, because many microservices are built with a continuous delivery mode to build and deploy features consistently, developers and DevOps teams need accurate and reliable testing strategies to be confident in these features. So which different types of tests exist for microservices, how can they work for other areas of your software, and what are their benefits? The well-known “testing pyramid” can provide a testing framework for approaching these tests. According to Martin Fowler, a prominent author on software engineering principles, “The ‘Test Pyramid’ is a metaphor to group software tests into buckets of different granularity.” The different layers of the pyramid are defined as: Note: some versions of the testing pyramid switch the order of component tests and integration tests. Combining multiple microservices testing strategies leads to high test coverage and confidence in your software while also making overall maintenance more manageable. Unit Testing Unit testing aims to ensure that the smallest portion of service performs as expected, within the specification that has been decided upon during the microservices design phase. Because microservices break down application functionality into hundreds of small testable functionality components, unit testing treats each one individually and independently. It’s best practice to unit test on the level of a class or that of a group of related classes. Unit testing can cut off a component’s dependencies by using test doubles such as fakes, stubs, mocks, dummies, and spies. For example, testers can mock the responses for your dependencies and “assume they do [X]” where [X] is the correct response, a failure response, etc. Component Testing Component testing verifies that a given service is functioning correctly.
