131-java-testing-unit-testing

name	131-java-testing-unit-testing
description	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. This should trigger for requests such as Review Java code for unit tests; Apply best practices for unit tests in Java code. Part of cursor-rules-java project
license	Apache-2.0
metadata	{"author":"Juan Antonio Breña Moral","version":"0.16.0"}

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//