# Spring Boot Testing

> Standards for unit, integration, and slice testing in Spring Boot 3. Use when writing unit tests, integration tests, or slice tests for Spring Boot 3 applications. (triggers: **/*Test.java, webmvctest, datajpatest, testcontainers, assertj)

- Skill: `hoangnguyen0403/spring-boot-testing-2` (Agent Skill)
- Install (CLI): `npx skillmds@latest add hoangnguyen0403/spring-boot-testing-2`
- Raw SKILL.md: https://api.skillmd.com/api/skills/hoangnguyen0403/spring-boot-testing-2/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: HoangNguyen0403 (https://skillmd.com/u/hoangnguyen0403)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/hoangnguyen0403/spring-boot-testing-2

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# Spring Boot Testing Standards

## **Priority: P0**

## Implementation Guidelines

### TDD Workflow

1.  **Red**: Write a failing test (e.g., `returns 404`).
2.  **Green**: Implement minimal code to pass.
3.  **Refactor**: Clean up while keeping tests green.
4.  **Coverage**: Verify with JaCoCo.

### Best Practices

- **Real Infrastructure**: Use **Testcontainers** for DB/Queues. See [Integration Template](references/testing-template.md). Avoid H2/Embedded.
- **Assertions**: Use **AssertJ** (`assertThat`) over JUnit assertions.
- **Isolation**: Use `@MockBean` for downstream dependencies in Slice Tests.

## Anti-Patterns

- **No Dirty Contexts**: Avoid @MockBean in base classes; it reloads context per test.
- **No network I/O in tests**: Mock external calls with WireMock.
- **No System.out in tests**: Use AssertJ assertions instead.

## References

- [Implementation Examples](references/implementation.md)