Overview
Testing prevents regressions and speeds up development. Spring Boot’s built-in testing tools allow fast, reliable, and isolated checks without the inefficiency of manual methods like Postman.
@Displayname- use this to explain what the test is doing
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Why
- Manual testing comes with several inconveniences:
- You have to start the server and open Postman every time, which is tedious.
- As the number of test cases grows, the repeated work becomes overwhelming.
- It’s difficult to test specific functions (e.g., a single method) in isolation.
| Category | Manual Testing | Automated Testing (e.g., Unit Tests) |
|---|---|---|
| Execution Method | Developer manually uses Postman, etc. | Click a button in the IDE or run automatically via CI |
| Repeatability | Inefficient, time-consuming | Can be repeated quickly |
| Scope of Verification | Broad (focused on checking overall flow) | Precise verification down to individual functions |
| Productivity | Low (burdensome when repeated) | High (done with a single click) |
| Refactoring Safety | Low | High |
Types of testing in Spring
Diagram
Types of tests
| Test Type | Main Purpose | Test Scope | Characteristics | Tool/Annotation | Code examples |
|---|---|---|---|---|---|
| Unit Test (단위 테스트) | Verify functionality of small units (methods, classes) | Very narrow | No Spring Context loaded. Extremely fast, completely isolated from other parts of the application. | - JUnit 5 - Mockito - AssertJ | - Example - service unit testing |
| Slice Test | Test specific layers in layered architecture (e.g., Controller, Repository) in isolation | Medium | Loads a partial Spring Context. Fast, but slower than a unit test. Uses mocks for dependencies outside the slice. | - @WebMvcTest (Controller)- [[Data Access (Repository) Layer Testing# @DataJpaTest|@DataJpaTest]]- Mockito | - Example - controller test |
| Integration Test (통합 테스트) | Verify interactions between multiple layers including database and services | Broad | Loads the full Spring Context. Slower, as it involves real components, network calls, and database connections. | @SpringBootTest TestRestTemplate@Transactional (for DB tests) | |
| Functional Test (기능 테스트) | Verify the application behaves correctly from the user/client perspective, testing multiple components - client vs server | Very Broad | Simulates real-world usage. Tests a complete feature workflow, often involving the entire running application. | External tools (Selenium, Postman), or full-stack @SpringBootTest |