Backend Testing Skill

When to Use

• Writing unit tests for services or repositories
• Writing controller tests with MockMvc
• Writing integration tests
• Reviewing test coverage or test quality

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Stack

• JUnit5 + Spring Boot Test
• MockMvc for controller tests
• (Optional) Testcontainers for integration tests

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Mandatory Rules

• Mocking Annotation: Do NOT use @MockBean. You MUST use @MockitoBean when replacing a bean in the Spring Test Context.
• Spying Annotation: Do NOT use @SpyBean. Use @MockitoSpyBean instead.
• Best Practices: Do not recommend or include @MockBean in any test examples, guides, or code reviews within this project.

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Minimum Requirements

Each endpoint requires:

• At least 1 success test
• At least 1 failure test

Document important endpoints with Spring REST Docs.

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What to Test

1. Validation errors - Invalid input handling
2. Authorization errors - If applicable
3. Idempotency behaviors - Duplicate request handling
4. TTL expiry behaviors - Session/token expiration

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Test Organization

src/test/java/
├── controller/
│   └── {Feature}ControllerTest.java
├── service/
│   └── {Feature}ServiceTest.java
└── integration/
    └── {Feature}IntegrationTest.java

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Test Naming Convention

@Test
void should_ReturnSuccess_When_ValidInput() { }

@Test
void should_ThrowException_When_InvalidInput() { }