SpringExtension for JUnit 5: Why Do We Need It?
SpringExtension integrates the Spring TestContext Framework into JUnit 5 Jupiter extension model, sets up the ApplicationContext, and manages dependencies.
Running JUnit Tests with Maven
Learn to run JUnit tests using Maven Surefire Plugin. We will learn to run a single test, run only selected tests or run all the tests in the project.
Spring Boot Mockito JUnit Example: Unit Test a Service
Unit test a Spring Boot service with JUnit and Mockito. Mock the repository with @Mock, build the service with @InjectMocks, stub with when().thenReturn() and check calls with verify(). Also covers @MockitoBean in @SpringBootTest, thenThrow, ArgumentCaptor, BDDMockito, strict stubs and the Mockito Java agent on Java 21+.
JUnit 5 vs JUnit 4: Differences and Migration Guide
JUnit 5 vs JUnit 4 compared with the same test in both versions, an annotation and rule mapping table, the Vintage engine and an OpenRewrite migration.
JUnit 5 assertThrows(): Check Exception Type, Message, Cause
JUnit 5 assertThrows() examples that check the exception type, message and cause, plus assertThrowsExactly(), assertDoesNotThrow() and JUnit 4 migration.
JUnit Assertions: assertEquals, assertAll and More (JUnit 5)
JUnit assertions explained with examples for JUnit 5 and 6, from assertEquals and assertAll to assertLinesMatch, assertInstanceOf, timeouts and fail().
Configure Log4j2 for JUnit Tests
Learn some recommended ways to configure Log4j2 – specific to junit testcases and different from used in production.
Test Spring Security Authentication with JUnit and MockMvc
Test Spring Security authentication with JUnit 6 and Spring Boot 4.1.1 using @WithMockUser, @WithUserDetails, httpBasic(), csrf() and 401 and 403 checks.
JUnit Test Listener: TestExecutionListener and RunListener
JUnit test listener examples for JUnit 6 and 4, a TestExecutionListener registered via ServiceLoader, a TestWatcher extension and a JUnit 4 RunListener.
JUnitCore and Launcher API: Run JUnit Tests from Java Code
JUnitCore runs JUnit 4 tests from code. Learn its JUnit 6 replacement, the Launcher API, with selectors, tag filters, summaries, fail fast and the console.
Unit Testing Best Practices in Java With JUnit
Write useful Java unit tests with JUnit. Learn clear assertions, boundary cases, independent setup, test doubles, exception checks and coverage limits.