There are five different microservices testing strategies. The first three of them are the same as for monolithic applications:
- Unit tests: With unit tests, we test the smallest pieces of code, for example, a single method or component, and mock every call of other methods and components. There are many popular frameworks that support unit tests in Java, such as JUnit, TestNG, and Mockito (for mocking). The main task of this type of testing is to confirm that the implementation meets requirements. Unit testing can be a powerful tool, especially when combined with test-driven development.
- Integration tests: Using only unit testing doesn't guarantee that you will verify the behavior of the whole system. Integration tests take the modules and try to test them together. This approach gives you an opportunity to exercise communication paths within the subsystem. We are testing the interaction and communication between components based on their interfaces with external services...