Deprecate TestUtils.dockerRegistryFromEnv()

The Testcontainers rely on the `TESTCONTAINERS_HUB_IMAGE_NAME_PREFIX` ENV var
and build proper image name automatically.

* Deprecate `TestUtils.dockerRegistryFromEnv()` and remove its usage in the project

Author: artembilan

spring-integration-jdbc/src/test/java/org/springframework/integration/jdbc/mysql/MySqlContainerTest.java

@@ -19,9 +19,6 @@
 import org.junit.jupiter.api.BeforeAll;
 import org.testcontainers.containers.MySQLContainer;
 import org.testcontainers.junit.jupiter.Testcontainers;
-import org.testcontainers.utility.DockerImageName;
-
-import org.springframework.integration.test.util.TestUtils;
 
 /**
  * The base contract for JUnit tests based on the container for MqSQL.

spring-integration-mqtt/src/test/java/org/springframework/integration/mqtt/MosquittoContainerTest.java

@@ -20,8 +20,6 @@
 import org.testcontainers.containers.GenericContainer;
 import org.testcontainers.junit.jupiter.Testcontainers;
 
-import org.springframework.integration.test.util.TestUtils;
-
 /**
  * The base contract for JUnit tests based on the container for MQTT Mosquitto broker.
  * The Testcontainers 'reuse' option must be disabled,so, Ryuk container is started
@@ -37,7 +35,7 @@
 public interface MosquittoContainerTest {
 
 	GenericContainer<?> MOSQUITTO_CONTAINER =
-			new GenericContainer<>(TestUtils.dockerRegistryFromEnv() + "eclipse-mosquitto:2.0.12")
+			new GenericContainer<>("eclipse-mosquitto:2.0.12")
 					.withCommand("mosquitto -c /mosquitto-no-auth.conf")
 					.withExposedPorts(1883);
 

spring-integration-test-support/src/main/java/org/springframework/integration/test/util/TestUtils.java

@@ -375,6 +375,12 @@ public static void revertLogLevels(String methodName, LevelsContainer container)
 		ctx.updateLoggers();
 	}
 
+	/**
+	 * Take a Docker Hub url from ENV var.
+	 * @return a Docker Hub url from ENV var.
+	 * @deprecated since 5.5.13 in favor of standard {@code TESTCONTAINERS_HUB_IMAGE_NAME_PREFIX} ENV var
+	 */
+	@Deprecated
 	public static String dockerRegistryFromEnv() {
 		return Optional.ofNullable(System.getenv("DOCKER_REGISTRY_URL")).orElse("");
 	}