131-java-testing-unit-testing
Java Unit testing guidelines
Review and improve Java unit tests using modern JUnit 5, AssertJ, and Mockito best practices.
What is covered in this Skill?
- JUnit 5 annotations:
@Test,@BeforeEach,@AfterEach,@DisplayName,@Nested,@ParameterizedTest - AssertJ fluent assertions:
assertThat,assertThatThrownBy - Given-When-Then test structure, descriptive test naming, single-responsibility tests
- Test independence and isolated state
- Parameterized tests:
@ValueSource/@CsvSource/@MethodSource - Mockito dependency mocking:
@Mock,@InjectMocks,MockitoExtension - Code coverage guidance (JaCoCo), package-private test visibility
- Testing anti-patterns: reflection, shared state, hard-coded values, testing implementation details
- Error handling:
assertThatThrownBy, exception messages - JSpecify null-safety:
@NullMarked,@Nullable - RIGHT-BICEP coverage principles, A-TRIP test quality, CORRECT boundary condition verification
Scope: The reference is organized by examples (good/bad code patterns) for each core area. Apply recommendations based on applicable examples.
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