Test Quality

This skill enforces modern Java testing practices with JUnit 5 and AssertJ assertions instead of old-school JUnit assertions. It activates when you say "add tests" or "improve test coverage" and pushes you toward readable patterns like the AAA structure, descriptive @DisplayName annotations, and AssertJ's fluent chains that actually tell you what failed. The source shows good taste: nested test classes for organization, extracting() for collection verification, and soft assertions when you need multiple checks. It steers you away from assertEquals toward assertThat() with clear failure messages. If you're still writing assertTrue and basic JUnit assertions, this will modernize your test style fast.

skills.sh installs: 336
GitHub stars: 771
last updated: Feb 8, 2026

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Install

$ npx -y skills add decebals/claude-code-java --skill test-quality --agent claude-code

Installs into .claude/skills of the current project.

Files

Test Quality Skill (JUnit 5 + AssertJ)

Write high-quality, maintainable tests for Java projects using modern best practices.

When to Use

Writing new test classes
Reviewing/improving existing tests
User asks to "add tests" / "improve test coverage"
Code review mentions missing tests

Framework Preferences

JUnit 5 (Jupiter)

import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Nested;
import static org.assertj.core.api.Assertions.*;

AssertJ over standard assertions

✅ Use AssertJ:

assertThat(plugin.getState())
    .as("Plugin should be started after initialization")
    .isEqualTo(PluginState.STARTED);

assertThat(plugins)
    .hasSize(3)
    .extracting(Plugin::getId)
    .containsExactly("plugin1", "plugin2", "plugin3");

❌ Avoid JUnit assertions:

assertEquals(PluginState.STARTED, plugin.getState()); // Less readable
assertTrue(plugins.size() == 3); // Less descriptive failures

Test Structure (AAA Pattern)

Always use Arrange-Act-Assert pattern:

SKILL.md on GitHub

Details

Repository: github.com/decebals/claude-code-java
Categories: Testing & QA, Code Review & Quality, Java & JVM
License: MIT
First seen: Jun 11, 2026

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