spring-webflux-testing

name	spring-webflux-testing
description	WebFlux testing requires StepVerifier for reactive streams — standard assertions silently pass on empty Flux. WebTestClient API differs from MockMvc. Read before testing reactive endpoints. Triggers: @WebFluxTest, WebTestClient, StepVerifier, Mono, Flux, mockUser(), mockJwt(), mutateWith, verifyComplete, expectBody, expectStatus, @AutoConfigureWebTestClient.
version	0.1.0
license	Apache-2.0

Spring WebFlux Testing

Signals: @WebFluxTest, WebTestClient, StepVerifier, Mono, Flux, mutateWith, mockUser(), mockJwt(), thenCancel, verifyComplete, withVirtualTime

Tested With

• Spring Boot 3.2+ / Spring Boot 4.x
• Spring Framework 6.x / Spring Framework 7.x
• Reactor Core 3.5+ / 3.7+
• Spring Security 6.x / 7.x (auto-configured in @WebFluxTest)
• JUnit 5

Do NOT Use This Skill When

• Testing Spring MVC (servlet-based) controllers → use spring-mvc-testing
• Testing Spring Security rules in a servlet-based application → use spring-security-testing
• Testing JPA repositories → use spring-jpa-testing
• Testing WebSocket or STOMP messaging → use spring-websocket-testing
• Writing pure unit tests for reactive service logic → use spring-testing-fundamentals for AssertJ/Mockito patterns, combine with StepVerifier for reactive

When to Read References

Situation	Read
Setting up @WebFluxTest, WebTestClient configuration	references/webflux-testing-patterns.md
GET, POST, PUT, DELETE with WebTestClient	references/webflux-testing-patterns.md
expectBody, expectBodyList, jsonPath assertions	references/webflux-testing-patterns.md
StepVerifier for Flux, Mono, error signals	references/webflux-testing-patterns.md
StepVerifier.withVirtualTime for time-based operators	references/webflux-testing-patterns.md
Testing reactive security with mutateWith(mockUser()), mockJwt()	references/webflux-testing-patterns.md
Testing SSE streams	references/webflux-testing-patterns.md
Boot 3.x → 4.x WebFlux testing changes	references/webflux-testing-patterns.md