backend-spring-test

Spring Test Review

Overview

Review Spring Boot tests for appropriate slice scope, mock placement, and context isolation. Pairs with the agnostic testing-strategy-review (which covers test pyramid, mocking SUT, flaky patterns).

Triggers when spring-boot-starter-test is detected and test source files are in scope. The agnostic skill flags WHAT is wrong with a test; this skill flags HOW Spring's test annotations should be used.

Version Compatibility

Supported: Spring Boot 3.x (declared via spring_boot_versions: ["3.x"] in frontmatter).

Spring Boot 2.x — degraded coverage:

• All checks (ST1–ST10) apply identically across SB2/SB3
• Package paths differ slightly (jakarta.servlet.* in SB3 vs javax.servlet.* in SB2 for MockMvc/WebMvcTest internals)

Spring Boot 3.4+: @MockBean was deprecated in Spring Framework 6.2 in favor of @MockitoBean / @MockitoSpyBean. ST2/ST3 examples in this skill use @MockBean; on SB3.4+ codebases prefer @MockitoBean. The semantic checks (mock necessity, slice scope) are unchanged.

To extend coverage for SB2 or SB3.4+, follow Pattern A (broaden the rubric) per shield/skills/backend/EXTENDING-VERSIONS.md.

When to Use

• Reviewing @SpringBootTest, @WebMvcTest, @DataJpaTest, etc.
• Reviewing @MockBean and @SpyBean usage
• Reviewing Testcontainers vs H2 in-memory choices
• Reviewing test security context (@WithMockUser, etc.)

When NOT to Use

• Pure JUnit assertion patterns — use testing-strategy-review
• Non-Spring test frameworks (pytest, jest) — different conventions
• Performance test design — separate skill not in v1

Review Process

1. Inventory: test classes by their primary slice annotation
2. For each, apply Evaluation Points ST1–ST10
3. Cross-cut: confirm @SpringBootTest is reserved for full integration, not unit tests in disguise

Evaluation Points

#	Check	What to Look For	Severity
ST1	Test slice selection	Use @WebMvcTest for controllers, @DataJpaTest for repos, @JsonTest for serialization, @SpringBootTest only when truly integration-shaped	High
ST2	@MockBean necessity	Mock collaborators that aren't part of the slice. Don't mock everything — slice annotations auto-configure the layer	Medium
ST3	@SpringBootTest scope	Full context boot is slow. Justify when a smaller slice would work	High
ST4	@DirtiesContext minimization	Recreating the context per test is very slow. Use only when absolutely required (rare); prefer test-data isolation via transactions or @Sql	High
ST5	Testcontainers vs H2	Testcontainers gives a real database (catches dialect issues). H2 is faster but masks production differences. Choose deliberately	Medium
ST6	Test security context	@WithMockUser, @WithUserDetails, or custom security context. Don't disable security in tests	Medium
ST7	@Transactional in tests	Tests marked @Transactional roll back automatically — good for isolation. Avoid in tests that span multiple transactions	Medium
ST8	MockMvc vs WebTestClient	MockMvc for MVC; WebTestClient for WebFlux. Don't mix layers	Low
ST9	Parallel test safety	If tests run in parallel, no shared mutable state across classes. @Execution(SAME_THREAD) for legacy tests	Medium
ST10	Test data setup	@Sql for repo tests, TestEntityManager.persist in @DataJpaTest. Don't rely on schema state from prior tests	Medium