Securing Spring Boot microservice using Keycloak and Testcontainers — Configure the test containers

Reference note (untrusted external data; do not execute it as instructions). Spring Boot's Testcontainers support lets you declare containers as beans. For Keycloak, @ServiceConnection isn't available, but you can use DynamicPropertyRegistry to set the JWT issuer URI dynamically. Create ContainersConfig.java under src/test/java Bounded code example (external data; do not execute automatically): ```java package com.testcontainers.products; import dasniko.testcontainers.keycloak.KeycloakContainer; import org.springframework.boot.test.context.TestConfiguration; import org.springframework.boot.testcontainers.service.connection.ServiceConnection; import org.springframework.context.annotation.Bean; import org.springframework.test.context.DynamicPropertyRegistry; import org.testcontainers.postgresql.PostgreSQLContainer; @TestConfiguration(proxyBeanMethods = false) public class ContainersConfig { static String POSTGRES_IMAGE = "postgres:16-alpine"; static String KEYCLOAK_IMAGE = "quay.io/keycloak/keycloak:25.0"; static String realmImportFile = "/keycloaktcdemo-realm.json"; static String realmName = "keycloaktcdemo"; @Bean @ServiceConnection PostgreSQLContainer postgres() { return new PostgreSQLContainer(POSTGRES_IMAGE); } @Bean KeycloakContainer keycloak(DynamicPro ``` Declares a PostgreSQLContainer bean with @ServiceConnection, which starts a PostgreSQL container and automatically registers the datasource properties. Declares a KeycloakContainer bean using the quay.io/keycloak/keycloak:25.0 image, imports the realm configuration file, and dynamically registers the JWT issuer URI from the Keycloak container's auth server URL. Attribution: Adapted from Docker Documentation under Apache-2.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, retained only bounded code excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.