JUnit vs Mockito

JUnit:

Unit Testing Framework:

JUnit is a widely-used Java unit testing framework for writing and executing unit tests for Java code.

Test Case Definition:

Developers define test cases by writing test methods annotated with @Test, where each method represents a specific test scenario.

Assertions:

JUnit provides a set of assertion methods (e.g., assertEquals, assertTrue, assertNotNull) to validate expected outcomes and behaviors of code under test.

Test Lifecycle:

JUnit manages the test lifecycle, providing hooks for setup (@Before), teardown (@After), and initialization (@BeforeClass, @AfterClass) methods to prepare test environments and clean up resources.

Parameterized Tests:

JUnit supports parameterized tests using @Parameterized or @MethodSource, allowing developers to run the same test method with different input values.

Test Suites:

Developers can organize related test classes into test suites using @RunWith and @Suite annotations, facilitating the execution and grouping of tests.

Integration with IDEs:

JUnit integrates seamlessly with popular IDEs like IntelliJ IDEA and Eclipse, providing features such as test runners, test result visualization, and code navigation for efficient test development and execution.

Continuous Integration:

JUnit is widely used in CI/CD pipelines with tools like Jenkins, Travis CI, and CircleCI, enabling automated test execution and continuous integration of Java projects.

Parallel Execution:

JUnit 5 introduced parallel test execution support, allowing tests to run concurrently for improved performance and reduced test execution time.

Compatibility:

JUnit is compatible with various testing tools and libraries, including mocking frameworks like Mockito for mocking dependencies in unit tests.

Mockito:

Mocking Framework:

Mockito is a popular Java mocking framework used for creating and configuring mock objects to simulate dependencies in unit tests.

Mock Object Creation:

Developers use Mockito to create mock objects representing dependencies or collaborators of the code under test, enabling isolated and focused unit testing.

Stubbing Behavior:

Mockito allows developers to define mock object behavior using methods like when, thenReturn, thenThrow, and doReturn, specifying return values or throwing exceptions for method invocations.

Verification:

Developers can verify method invocations on mock objects using Mockito's verification methods like verify, verifyZeroInteractions, and verifyNoMoreInteractions, ensuring that the expected interactions occurred during test execution.

Mocking Final Classes and Methods:

Mockito supports mocking of final classes and methods using plugins like Mockito-inline or PowerMockito, enabling mocking of previously unmockable classes and methods for testing.

Spying:

Mockito allows developers to create spy objects using the spy method, enabling partial mocking of real objects while retaining their original behavior for certain methods.

Annotations:

Mockito provides annotations like @Mock, @Spy, and @InjectMocks to simplify the creation and injection of mock objects and dependencies into test classes.

Argument Matchers:

Mockito offers argument matchers like any, eq, argThat, and anyInt to specify flexible and expressive argument matching for method invocations on mock objects.

Mockito Extensions:

Mockito supports extensions and plugins for advanced mocking capabilities, such as verification of interactions with collaborators, stubbing of static methods, and mocking of final classes and enums.

Documentation and Community Support:

Mockito provides comprehensive documentation, tutorials, and community support, making it easy for developers to learn and apply mocking techniques effectively in unit tests.