Java Testing

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 (L24-L31)
• Quick Start (L57-L77)
• Key Patterns (L78-L87)
• Mocking Patterns (L88-L123)
• Persistence Testing (L124-L139)
• References (L140-L147)
• Related Rules (L148-L152)
• Related Skills (L153-L158)

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

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

Related Skills