For example, we can test our example from Chapter 22, EnableReactiveMethodSecurity using the same setup and annotations we did in Section 9.1, “Testing Method Security”. Here is a minimal sample of what we can do:

@RunWith(SpringRunner.class)
@ContextConfiguration(classes = HelloWebfluxMethodApplication.class)
public class HelloWorldMessageServiceTests {
    @Autowired
    HelloWorldMessageService messages;

    @Test
    public void messagesWhenNotAuthenticatedThenDenied() {
        StepVerifier.create(this.messages.findMessage())
            .expectError(AccessDeniedException.class)
            .verify();
    }

    @Test
    @WithMockUser
    public void messagesWhenUserThenDenied() {
        StepVerifier.create(this.messages.findMessage())
            .expectError(AccessDeniedException.class)
            .verify();
    }

    @Test
    @WithMockUser(roles = "ADMIN")
    public void messagesWhenAdminThenOk() {
        StepVerifier.create(this.messages.findMessage())
            .expectNext("Hello World!")
            .verifyComplete();
    }
}

Spring Security provides integration with WebTestClient. The basic setup looks like this:

@RunWith(SpringRunner.class)
@ContextConfiguration(classes = HelloWebfluxMethodApplication.class)
public class HelloWebfluxMethodApplicationTests {
    @Autowired
    ApplicationContext context;

    WebTestClient rest;

    @Before
    public void setup() {
        this.rest = WebTestClient
            .bindToApplicationContext(this.context)
            // add Spring Security test Support
            .apply(springSecurity())
            .configureClient()
            .filter(basicAuthentication())
            .build();
    }
    // ...
}

@Test
public void messageWhenNotAuthenticated() throws Exception {
    this.rest
        .get()
        .uri("/message")
        .exchange()
        .expectStatus().isUnauthorized();
}

// --- WithMockUser ---

@Test
@WithMockUser
public void messageWhenWithMockUserThenForbidden() throws Exception {
    this.rest
        .get()
        .uri("/message")
        .exchange()
        .expectStatus().isEqualTo(HttpStatus.FORBIDDEN);
}

@Test
@WithMockUser(roles = "ADMIN")
public void messageWhenWithMockAdminThenOk() throws Exception {
    this.rest
        .get()
        .uri("/message")
        .exchange()
        .expectStatus().isOk()
        .expectBody(String.class).isEqualTo("Hello World!");
}

// --- mutateWith mockUser ---

@Test
public void messageWhenMutateWithMockUserThenForbidden() throws Exception {
    this.rest
        .mutateWith(mockUser())
        .get()
        .uri("/message")
        .exchange()
        .expectStatus().isEqualTo(HttpStatus.FORBIDDEN);
}

@Test
public void messageWhenMutateWithMockAdminThenOk() throws Exception {
    this.rest
        .mutateWith(mockUser().roles("ADMIN"))
        .get()
        .uri("/message")
        .exchange()
        .expectStatus().isOk()
        .expectBody(String.class).isEqualTo("Hello World!");
}

this.rest
    // provide a valid CSRF token
    .mutateWith(csrf())
    .post()
    .uri("/login")
    ...