# Java Testing

> Java testing guidelines using Spock Framework and Groovy. Covers test structure, mocking patterns, persistence testing with Testcontainers, gRPC testing, and Spring Boot test configurations. Use when writing or reviewing tests.

- Skill: `majiayu000/java-testing-2` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add majiayu000/java-testing-2`
- Raw SKILL.md: https://api.skillmd.com/api/skills/majiayu000/java-testing-2/raw
- Safety review: pending (external: skill-scanner PASS, skillspector CAUTION)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: majiayu000 (https://skillmd.com/u/majiayu000)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/majiayu000/java-testing-2

---


# Java Testing

Guidelines for writing tests in Java projects using the Spock Framework and Groovy.

## When to use this skill

- Writing new tests
- Reviewing test code
- Setting up test infrastructure
- Configuring Testcontainers
- Mocking dependencies in Spring Boot tests

## Skill Contents

### Sections

- [When to use this skill](#when-to-use-this-skill) (L24-L31)
- [Quick Start](#quick-start) (L57-L77)
- [Key Patterns](#key-patterns) (L78-L87)
- [Mocking Patterns](#mocking-patterns) (L88-L123)
- [Persistence Testing](#persistence-testing) (L124-L139)
- [References](#references) (L140-L147)
- [Related Rules](#related-rules) (L148-L152)
- [Related Skills](#related-skills) (L153-L158)

### Available Resources

**📚 references/** - Detailed documentation
- [grpc testing](references/grpc-testing.md)
- [junit5 migration](references/junit5-migration.md)
- [spock patterns](references/spock-patterns.md)
- [test setup workflow](references/test-setup-workflow.md)
- [test utilities](references/test-utilities.md)
- [testcontainers setup](references/testcontainers-setup.md)

---

## Quick Start

### 1. Test Structure

```groovy
def "should do Y when X"() {
    given:
        // create test data
    when:
        // execute process
    then:
        // assert output
    where: // use test table if suited
}
```

### 2. Test Naming

- Test files: `<ClassName>Spec.groovy`
- Test methods: `"should [expected behavior] when [condition]"`

## Key Patterns

| Pattern | When to Use |
|---------|-------------|
| **Spock Mock** | Unit tests without Spring context |
| **@SpringBean** | Spring integration tests with mocks |
| **@ServiceConnection** | Testcontainers database connection |
| **InProcessServer** | gRPC client/server testing |
| **Data Tables** | Multiple test cases with same structure |

## Mocking Patterns

### Unit Tests (No Spring)

```groovy
class SomeSpec extends Specification {
    SomeInterface someInterface = Mock()

    def "test method"() {
        given:
            def underTest = new ClassUnderTest(someInterface)
        when:
            // call method
        then:
            1 * someInterface.someMethod("value") >> responseClass
    }
}
```

### Spring Integration Tests

```groovy
@SpringBootTest
class SomeSpec extends Specification {
    @SpringBean
    SomeInterface someInterface = Mock()

    def "test method"() {
        when:
            // call method
        then:
            1 * someInterface.someMethod(_) >> { throw new RuntimeException() }
    }
}
```

## Persistence Testing

Use Testcontainers with `@ServiceConnection` for database tests:

```groovy
@Configuration
class IntegrationTestConfiguration {
    @Bean
    @ServiceConnection
    PostgreSQLContainer<?> postgreSQLContainer() {
        return new PostgreSQLContainer<>("postgres:14-alpine")
                .withDatabaseName("test_db")
    }
}
```

## References

| Reference | Description |
|-----------|-------------|
| [references/spock-patterns.md](references/spock-patterns.md) | Advanced Spock patterns |
| [references/testcontainers-setup.md](references/testcontainers-setup.md) | Testcontainers configuration |
| [references/grpc-testing.md](references/grpc-testing.md) | gRPC test patterns |

## Related Rules

- `.cursor/rules/java-testing-guidelines.mdc` - Full testing reference
- `.cursor/rules/java-flyway-migrations.mdc` - Flyway for test schema

## Related Skills

| Skill | Purpose |
|-------|---------|
| [java-coverage](../java-coverage/SKILL.md) | JaCoCo test coverage |
| [gradle-standards](../gradle-standards/SKILL.md) | Test dependency bundles |
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