java-testing

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
• Quick Start
• Key Patterns
• Mocking Patterns
• Persistence Testing
• References
• Related Rules
• Related Skills

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

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)

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

Reference	Description
references/spock-patterns.md	Advanced Spock patterns
references/testcontainers-setup.md	Testcontainers configuration
references/grpc-testing.md	gRPC test patterns

Related Rules

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

Related Skills

Skill	Purpose
java-coverage	JaCoCo test coverage
gradle-standards	Test dependency bundles