name: java-testing description: > 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. compatibility: Java projects using Spock Framework metadata: version: "2.0.0" technology: java category: testing tags: - java - testing - spock - groovy - testcontainers

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
• When asked to "improve test setup" or "run all tests and fix"

Skill Contents

Sections

• When to use this skill (L24-L32)
• Quick Start (L58-L78)
• Key Patterns (L79-L88)
• Mocking Patterns (L89-L124)
• Persistence Testing (L125-L140)
• References (L141-L148)
• Related Rules (L149-L153)
• Related Skills (L154-L159)

Available Resources

📚 references/ - Detailed documentation

• grpc testing
• junit5 migration
• spock patterns
• test setup workflow
• test utilities
• testcontainers setup

Quick Start

1. Test Structure

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

Mocking Patterns

Unit Tests (No Spring)

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

@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:

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

References

Related Rules

• java-testing-guidelines - Full testing reference
• java-flyway-migrations - Flyway for test schema

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