Code review comment: That should be in `KeycloakRealmResourceManager` ? I see, please introduce a dedicated client id, same as I did for the jwt. though it has not been merget yet :-)

Code under review:
public void testRPInitiatedLogout() throws IOException, InterruptedException {
        Keycloak keycloak = KeycloakRealmResourceManager.createKeycloakClient();

        RealmResource realm = keycloak.realm(KeycloakRealmResourceManager.KEYCLOAK_REALM);
        RealmRepresentation representation = realm
                .toRepresentation();

        Integer ssoSessionMaxLifespan = representation.getSsoSessionMaxLifespan();
        representation.setSsoSessionMaxLifespan(20);

        Integer accessCodeLifespan = representation.getAccessCodeLifespan();
        representation.setAccessTokenLifespan(5);

        realm.update(representation);

        try (final WebClient webClient = createWebClient()) {
            HtmlPage page = webClient.getPage("http:
            assertEquals("Log in to quarkus", page.getTitleText());
            HtmlForm loginForm = page.getForms().get(0);
            loginForm.getInputByName("username").setValueAttribute("alice");
            loginForm.getInputByName("password").setValueAttribute("alice");
            page = loginForm.getInputByName("login").click();
            assertTrue(page.asText().contains("Tenant Logout"));
            assertNotNull(getSessionCookie(webClient));

            page = webClient.getPage("http:
            assertTrue(page.asText().contains("You were logged out"));
            assertNull(getSessionCookie(webClient));

            page = webClient.getPage("http:
            assertEquals("Log in to quarkus", page.getTitleText());
            loginForm = page.getForms().get(0);
            loginForm.getInputByName("username").setValueAttribute("alice");
            loginForm.getInputByName("password").setValueAttribute("alice");
            page = loginForm.getInputByName("login").click();
            assertTrue(page.asText().contains("Tenant Logout"));

            
            await().atMost(10, TimeUnit.SECONDS)
                    .pollInterval(Duration.ofSeconds(5))
                    .until(new Callable<Boolean>() {
                        @Override
                        public Boolean call() throws Exception {
                            webClient.getOptions().setRedirectEnabled(false);
                            WebResponse webResponse = webClient
                                    .loadWebResponse(new WebRequest(URI.create("http:
                            
                            assertEquals(200, webResponse.getStatusCode());
                            assertTrue(webResponse.getContentAsString().contains("Tenant Logout"));
                            assertNotNull(getSessionCookie(webClient));
                            return true;
                        }
                    });
        } finally {
            representation.setSsoSessionMaxLifespan(ssoSessionMaxLifespan);
            representation.setAccessTokenLifespan(accessCodeLifespan);
            realm.update(representation);
        }
    }

Line commented on: Keycloak keycloak = KeycloakRealmResourceManager.createKeycloakClient();

Revised code:
public void testRPInitiatedLogout() throws IOException {
        try (final WebClient webClient = createWebClient()) {
            HtmlPage page = webClient.getPage("http:
            assertEquals("Log in to logout-realm", page.getTitleText());
            HtmlForm loginForm = page.getForms().get(0);
            loginForm.getInputByName("username").setValueAttribute("alice");
            loginForm.getInputByName("password").setValueAttribute("alice");
            page = loginForm.getInputByName("login").click();
            assertTrue(page.asText().contains("Tenant Logout"));
            assertNotNull(getSessionCookie(webClient));

            page = webClient.getPage("http:
            assertTrue(page.asText().contains("You were logged out"));
            assertNull(getSessionCookie(webClient));

            page = webClient.getPage("http:
            assertEquals("Log in to logout-realm", page.getTitleText());
            loginForm = page.getForms().get(0);
            loginForm.getInputByName("username").setValueAttribute("alice");
            loginForm.getInputByName("password").setValueAttribute("alice");
            page = loginForm.getInputByName("login").click();
            assertTrue(page.asText().contains("Tenant Logout"));

            Cookie sessionCookie = getSessionCookie(webClient);
            assertNotNull(sessionCookie);
            String idToken = getIdToken(sessionCookie);

            
            await().atMost(10, TimeUnit.SECONDS)
                    .pollInterval(Duration.ofSeconds(1))
                    .until(new Callable<Boolean>() {
                        @Override
                        public Boolean call() throws Exception {
                            webClient.getOptions().setRedirectEnabled(false);
                            WebResponse webResponse = webClient
                                    .loadWebResponse(new WebRequest(URI.create("http:
                            
                            Cookie newSessionCookie = getSessionCookie(webClient);
                            assertNotNull(newSessionCookie);
                            return !idToken.equals(getIdToken(newSessionCookie));
                        }
                    });

            
            page = webClient.getPage("http:
            assertTrue(page.asText().contains("Tenant Logout"));
            assertNotNull(getSessionCookie(webClient));

            
            await().atMost(20, TimeUnit.SECONDS)
                    .pollInterval(Duration.ofSeconds(1))
                    .until(new Callable<Boolean>() {
                        @Override
                        public Boolean call() throws Exception {
                            webClient.getOptions().setRedirectEnabled(false);
                            WebResponse webResponse = webClient
                                    .loadWebResponse(new WebRequest(URI.create("http:
                            
                            int statusCode = webResponse.getStatusCode();

                            if (statusCode == 302) {
                                assertNull(getSessionCookie(webClient));
                                return true;
                            }

                            return false;
                        }
                    });

            
            webClient.getOptions().setRedirectEnabled(true);
            page = webClient.getPage("http:
            assertNull(getSessionCookie(webClient));
            assertEquals("Log in to logout-realm", page.getTitleText());
        }
    }