Spring Boot 4 testing strategies and patterns. Use when writing unit tests, slice tests (@WebMvcTest, @DataJpaTest), integration tests, Testcontainers with @ServiceConnection, security testing (@WithMockUser, JWT), or Modulith event testing with Scenario API. Covers the critical @MockitoBean migration from @MockBean.
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See how to installReview the instructions the agent will receive before you install.
Comprehensive testing patterns including slice tests, Testcontainers, security testing, and Modulith Scenario API.
| Old (Boot 3.x) | New (Boot 4.x) | Notes |
|---|---|---|
@MockBean | @MockitoBean | Required migration |
@SpyBean | @MockitoSpyBean | Required migration |
MockMvc (procedural) | MockMvcTester (fluent) | New AssertJ-style API |
Implicit @AutoConfigureMockMvc | Explicit annotation required | Add to @SpringBootTest |
New fluent, AssertJ-style API for controller testing:
@WebMvcTest(UserController.class)
class UserControllerTest {
@Autowired
private MockMvcTester mvc; // NEW: Fluent API
@Test
void getUser_returnsUser() {
mvc.get().uri("/users/{id}", 1)
.exchange()
.assertThat()
.hasStatusOk()
.bodyJson()
.extractingPath("$.name")
.isEqualTo("John");
}
}
Key Benefits: Fluent assertions, better error messages, AssertJ integration.
| Test Type | Annotation | Use When |
|---|---|---|
| Controller | @WebMvcTest | Testing request/response, validation |
| Repository | @DataJpaTest | Testing queries, entity mapping |
| JSON | @JsonTest | Testing serialization/deserialization |
| REST Client | @RestClientTest | Testing external API clients |
| Full Integration | @SpringBootTest | End-to-end, with real dependencies |
| Module | @ApplicationModuleTest | Testing bounded context in isolation |
@MockitoBean for external services@ServiceConnection for databasesMockMvcTester (new), RestTestClient (new), WebTestClient@WithMockUser, JWT mockingSee EXAMPLES.md for complete working examples including:
MockMvcTester and @MockitoBean (Java + Kotlin)TestEntityManager for lazy loading verification@ServiceConnection for PostgreSQL/Redis@WithMockUser for role-based accessScenario API| Anti-Pattern | Fix |
|---|---|
Using @MockBean in Boot 4 | Replace with @MockitoBean |
@SpringBootTest for unit tests | Use appropriate slice annotation |
Missing entityManager.clear() | Add to verify lazy loading |
| High-cardinality test data | Use minimal, focused fixtures |
| Shared mutable test state | Use @DirtiesContext or fresh containers |
| No security tests | Add @WithMockUser tests for endpoints |
| Need | Skill |
|---|---|
| Security configuration | spring-boot-security |
| Module boundaries | spring-boot-modulith |
| Data layer patterns | spring-boot-data-ddd |
| Controller patterns | spring-boot-web-api |
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Create, review, and manage Architecture Decision Records (ADRs) with auto-numbering, template detection, quality review, and index maintenance. Use when user mentions "ADR", "architecture decision", "document this decision", "create ADR", "review ADR", editing ADR files (docs/adr/, doc/adr/, .adr/), or discussing architectural choices and tradeoffs.
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Analyze system architecture, module structure, API contracts, data models, and code patterns. Use when designing systems, reviewing module boundaries, evaluating API designs, analyzing data models, checking pattern conformance, tracing decisions, or reviewing frontend architecture. Triggers: "architecture", "module design", "API design", "data model", "boundaries", "patterns", "decisions", "frontend architecture".
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Converts natural-language descriptions or UI spec files into optimized Google Stitch prompts. Use when creating, refining, or validating design directives for Google Stitch. Use when user says "create a Stitch prompt", "optimize this for Stitch", "convert this spec to a Stitch prompt", "write a UI prompt", or mentions Google Stitch prompt authoring. Follows Stitch best practices with short, directive prompts focused on screens, structure, and visual hierarchy.
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Zero-dependency live-preview server providing an agent↔browser bidirectional companion. Watches a content directory, wraps HTML fragments in a frame template, broadcasts live-reload over WebSocket, and captures browser-side click events to a JSONL file. Use when an agent needs to show HTML to the user in a browser and react to clicks — mockups, design exploration, gallery browsing, multi-select choices, prototype iteration. Triggered by "live preview", "browser companion", "preview server", "browser mockup", "show in browser", "arkhe-preview", or any skill that wants to write HTML fragments and have the user see them reload in real time.
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Deletes merged git branches (local and remote) and flags stale unmerged branches for manual review. Use when user mentions "cleanup branches", "delete merged branches", "prune old branches", "remove stale branches", "branch cleanup", or runs /cleanup-branches command.
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Interactive Claude Code environment setup wizard. Detects existing configuration, guides through best-practice setup for Global CLAUDE.md, project scaffolding, MCP servers, hooks, custom agents, keybindings, and settings. Use when user runs /devtools:code-env-setup, mentions "setup claude code", "configure claude", "claude code setup", "environment setup", or "initialize claude code".
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