unit-test-service-layer
Master isolated service layer testing using Mockito to mock repositories and external clients without database or API calls. This skill teaches you to arrange test data, verify method interactions, and handle exception scenarios with AssertJ assertions.
Unit Test Service Layer teaches you to write isolated Mockito-based tests for service classes with mocked dependencies and verified interactions.
AI-generated summary based on this skill's SKILL.md
Decision gist · record as of 2026-06-22
Unit Test Service Layer teaches you to write isolated Mockito-based tests for service classes with mocked dependencies and verified interactions. Master isolated service layer testing using Mockito to mock repositories and external clients without database or API calls. This skill teaches you to arrange test data, verify method interactions, and handle exception scenarios with AssertJ assertions.
Use it when
- unit-test-service-layer demonstrates how to mock repository and external dependency calls to simulate various scenarios.
- unit-test-service-layer covers arranging test conditions with mocked dependencies, executing service methods under controlled conditions.
Verify before relying
Read SKILL.md below before installing (2 files). Open directory: indexed for reading, not audited.
Install
giuseppe-trisciuoglio/developer-kit/unit-test-service-layer · repository language: Python
Open directory. Skills are indexed for reading, not audited. Review a skill's body before installing it.
Frequently asked questions
AI-generated answers based on this skill's SKILL.md and metadata
How to unit test service layer with Mockito?
unit-test-service-layer teaches you to isolate service classes by mocking their dependencies—repositories, external clients, and collaborators. Use @Mock to create mock objects, @InjectMocks to inject them into your service under test, and @ExtendWith(MockitoExtension.class) to enable Mockito annotations. Arrange test data with when/thenReturn, execute the service method, then assert outcomes with AssertJ. This approach eliminates database and API calls, keeping tests fast and focused on business logic.
What patterns does unit-test-service-layer cover for mocking repositories?
unit-test-service-layer demonstrates how to mock repository and external dependency calls to simulate various scenarios. Use Mockito's when().thenReturn() to stub successful responses, when().thenThrow() to simulate exceptions, and verify() to confirm your service called collaborators correctly. Mock repository methods return test data directly, letting you test service logic in complete isolation without touching a real database.
How do I test service business logic and error scenarios in isolation?
unit-test-service-layer covers arranging test conditions with mocked dependencies, executing service methods under controlled conditions, and asserting both happy-path and exception-handling outcomes. Mock external calls to return errors or throw exceptions, then verify your service handles them properly. This isolation ensures you test only the service's own logic, not infrastructure or third-party behavior.
Can unit-test-service-layer help verify service method interactions?
Yes. unit-test-service-layer teaches you to use Mockito's verify() to confirm your service called collaborators with the right arguments, the correct number of times, and in the expected order. Combine verify() with argument matchers to assert precise interaction patterns. This ensures your service orchestrates its dependencies correctly without relying on actual implementations.
Why use unit-test-service-layer for fast, isolated service tests?
unit-test-service-layer eliminates database connections, API calls, and external service dependencies by replacing them with Mockito mocks. Tests run in milliseconds instead of seconds, execute reliably without network or infrastructure, and remain deterministic. This speed and isolation make your test suite maintainable and suitable for continuous integration pipelines.
What is the @Mock and @InjectMocks setup in unit-test-service-layer?
unit-test-service-layer uses @Mock to declare dependencies you want to mock, and @InjectMocks to automatically inject those mocks into your service class. Pair this with @ExtendWith(MockitoExtension.class) on your test class. This setup eliminates manual mock creation and wiring, letting you focus on arranging behavior with when/thenReturn and verifying interactions with verify().
SKILL.md
Rendered from the published skill. Quoted content, verbatim.
Unit Testing Service Layer with Mockito
Overview
Provides patterns for unit testing @Service classes using Mockito. Mocks repository calls, verifies method invocations, tests exception scenarios, and stubs external API responses. Enables fast, isolated tests without Spring container or database.
When to Use
- Testing business logic in
@Serviceclasses - Mocking repository and external client dependencies
- Verifying service interactions with mocked collaborators
- Testing error handling and edge cases in services
- Writing fast, isolated unit tests (no database, no API calls)
Instructions
Follow this workflow to test service layer with Mockito, including validation checkpoints:
1. Setup Test Class
Use @ExtendWith(MockitoExtension.class) to enable Mockito
(truncated - see the full file via the links below)
File tree — 2 files
plugins/developer-kit-java/skills/unit-test-service-layer/SKILL.md
plugins/developer-kit-java/skills/unit-test-service-layer/references/examples.md
Let your AI agent find skills like this
Example. Real query, live index.
You found this page by searching. An agent finds it by wishing: SkillFed indexes 56,283 agent skills by what they can do, searchable in plain language.
wish › “Learn how to unit test service layer classes using Mockito mocks”
Give your agent the search over MCP, or paste the wish link into any chat. No install? Search from any chat →
Related skills
This skill teaches patterns for unit testing Spring ApplicationEvent publishers and @EventListener consumers using JUnit 5 and Mockito, without booting the full Spring context. Learn to mock ApplicationEventPublisher, capture events with ArgumentCaptor, verify listener side effects, and test async event handling. Covers error scenarios and best practices for keeping event tests isolated and deterministic.
This skill equips you to write robust JUnit 5 tests in Java, from basic assertions and exception handling to parameterized test cases and Mockito-driven mocking. It covers lifecycle management, nested test organization, and anti-patterns to avoid, with quick reference commands for Maven and Gradle execution.
Learn to unit test Spring REST controllers using MockMvc with mocked service dependencies. This skill covers testing HTTP methods, validating responses with JsonPath, handling errors, checking headers, and verifying content negotiation—all with focused examples for GET, POST, PUT, and DELETE endpoints.
Automatically generate well-structured JUnit 5 test cases for Java classes, complete with Mockito mocking, parameterized test scenarios, and edge case handling. The skill follows Arrange-Act-Assert patterns, creates tests for exception handling, verifies mock interactions, and targets high test coverage across service layers and Spring Boot components.
Build reliable unit tests for Java applications using JUnit 5, Mockito, and AssertJ with support for mocking, parameterized tests, and fluent assertions. Includes integration testing patterns with Testcontainers and Spring Boot Test, plus TDD and test coverage best practices to improve code quality.
Spring Boot Test Patterns guides you through layered testing strategies—from fast unit tests with mocked dependencies to full integration tests with real databases via Testcontainers. Learn focused slice testing with @DataJpaTest and @WebMvcTest, REST API testing with MockMvc, and container setup using @ServiceConnection for Spring Boot 3.5+.
More skills unit-test-caching (MIT) · unit-test-utility-methods (MIT) · testing (MIT) · test-generator (MIT)