JUnit, TestNG, Mockito
Mockito is a popular open-source Java testing framework used for creating mock objects in unit testing. It allows developers to simulate the behavior of complex dependencies or external components without relying on actual implementations. By using mocks, developers can isolate the code under test, ensuring that unit tests are focused, reliable, and faster to execute. Mockito works seamlessly with JUnit and TestNG, making it a standard choice for Java developers practicing Test-Driven Development (TDD) or Behavior-Driven Development (BDD).
Mockito provides a simple and readable API to create, configure, and verify mock objects. It supports features like stubbing method calls, verifying interactions, and capturing arguments. This helps developers test scenarios that are difficult or time-consuming to reproduce in a real environment, such as network calls, database operations, or external API interactions.