How do I install the 131 Java Testing Unit Testing skill?

Run npx skillmds add majiayu000/131-java-testing-unit-testing-2 in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is 131 Java Testing Unit Testing safe to use?

This skill has not completed SkillMD's automated safety review yet. Capability flags: docs only. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with 131 Java Testing Unit Testing?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is 131 Java Testing Unit Testing free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published 131 Java Testing Unit Testing?

majiayu000 (@majiayu000) published this skill. Their other Agent Skills are listed on their SkillMD profile.

131 Java Testing Unit Testing by majiayu000

Name: 131 Java Testing Unit Testing
Rating: 4.666666666666667 (3 reviews)
Author: majiayu000

131 Java Testing Unit Testing

Use when you need to review, improve, or write Java unit tests — including migrating from JUnit 4 to JUnit 5, adopting AssertJ for fluent assertions, structuring tests with Given-When-Then, ensuring test independence, applying parameterized tests, mocking dependencies with Mockito, verifying boundary conditions (RIGHT-BICEP, CORRECT, A-TRIP), leveraging JSpecify null-safety annotations, or eliminating testing anti-patterns such as reflection-based tests or shared mutable state.

majiayu000 3185c32 2 files · 3.5 KB Updated Sep 9, 2026 567 repo stars

File contents

Java Unit testing guidelines

Review and improve Java unit tests using modern JUnit 5, AssertJ, and Mockito best practices.

Core areas: 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 with @ValueSource/@CsvSource/@MethodSource, Mockito dependency mocking (@Mock, @InjectMocks, MockitoExtension), code coverage guidance (JaCoCo), package-private test visibility, code-splitting strategies (small methods, helper functions), testing anti-patterns (reflection, shared state, hard-coded values, testing implementation details), state management (immutable objects, @BeforeEach reset), error handling (assertThatThrownBy, exception messages), JSpecify null-safety (@NullMarked, @Nullable), RIGHT-BICEP coverage principles, A-TRIP test quality characteristics, and CORRECT boundary condition verification.

Prerequisites: Run ./mvnw compile or mvn compile before applying any change. If compilation fails, stop immediately and do not proceed — compilation failure is a blocking condition.

Multi-step scope: Step 1 validates the project compiles. Step 2 analyzes existing tests and categorizes issues by impact (CRITICAL, MAINTAINABILITY, PERFORMANCE, COVERAGE, RELIABILITY). Step 3 migrates to JUnit 5 with modern annotations. Step 4 adopts AssertJ for expressive assertions. Step 5 restructures tests using Given-When-Then with descriptive naming. Step 6 ensures test independence by eliminating shared state and order dependencies. Step 7 adds parameterized tests and boundary-condition coverage. Step 8 integrates Mockito mocking for external dependencies.

Before applying changes: Read the reference for detailed examples, good/bad patterns, and constraints.

Reference

For detailed guidance, examples, and constraints, see references/131-java-unit-testing.md.

---name: 131-java-testing-unit-testing-2description: Use when you need to review, improve, or write Java unit tests — including migrating from JUnit 4 to JUnit 5, adopting AssertJ for fluent assertions, structuring tests with Given-When-Then, ensuring test independence, applying parameterized tests, mocking dependencies with Mockito, verifying boundary conditions (RIGHT-BICEP, CORRECT, A-TRIP), leveraging JSpecify null-safety annotations, or eliminating testing anti-patterns such as reflection-based tests or shared mutable state.---# Java Unit testing guidelines Review and improve Java unit tests using modern JUnit 5, AssertJ, and Mockito best practices. **Core areas:** 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 with `@ValueSource`/`@CsvSource`/`@MethodSource`, Mockito dependency mocking (`@Mock`, `@InjectMocks`, `MockitoExtension`), code coverage guidance (JaCoCo), package-private test visibility, code-splitting strategies (small methods, helper functions), testing anti-patterns (reflection, shared state, hard-coded values, testing implementation details), state management (immutable objects, `@BeforeEach` reset), error handling (`assertThatThrownBy`, exception messages), JSpecify null-safety (`@NullMarked`, `@Nullable`), RIGHT-BICEP coverage principles, A-TRIP test quality characteristics, and CORRECT boundary condition verification. **Prerequisites:** Run `./mvnw compile` or `mvn compile` before applying any change. If compilation fails, **stop immediately** and do not proceed — compilation failure is a blocking condition. **Multi-step scope:** Step 1 validates the project compiles. Step 2 analyzes existing tests and categorizes issues by impact (CRITICAL, MAINTAINABILITY, PERFORMANCE, COVERAGE, RELIABILITY). Step 3 migrates to JUnit 5 with modern annotations. Step 4 adopts AssertJ for expressive assertions. Step 5 restructures tests using Given-When-Then with descriptive naming. Step 6 ensures test independence by eliminating shared state and order dependencies. Step 7 adds parameterized tests and boundary-condition coverage. Step 8 integrates Mockito mocking for external dependencies. **Before applying changes:** Read the reference for detailed examples, good/bad patterns, and constraints. ## Reference For detailed guidance, examples, and constraints, see [references/131-java-unit-testing.md](references/131-java-unit-testing.md).

Frequently asked questions