Add smoke test for Kafka with SSL

Closes gh-38260

spring-boot-tests/spring-boot-smoke-tests/spring-boot-smoke-test-kafka/build.gradle

@@ -14,4 +14,5 @@ dependencies {
 	testImplementation("org.springframework.kafka:spring-kafka-test") {
 		exclude group: "commons-logging", module: "commons-logging"
 	}
+	testImplementation("org.testcontainers:junit-jupiter")
 }

spring-boot-tests/spring-boot-smoke-tests/spring-boot-smoke-test-kafka/src/main/java/smoketest/kafka/Consumer.java

@@ -23,7 +23,7 @@ import org.springframework.kafka.annotation.KafkaListener;
 import org.springframework.stereotype.Component;
 
 @Component
-class Consumer {
+public class Consumer {
 
 	private final List<SampleMessage> messages = new CopyOnWriteArrayList<>();
 
@@ -33,7 +33,7 @@ class Consumer {
 		System.out.println("Received sample message [" + message + "]");
 	}
 
-	List<SampleMessage> getMessages() {
+	public List<SampleMessage> getMessages() {
 		return this.messages;
 	}
 

spring-boot-tests/spring-boot-smoke-tests/spring-boot-smoke-test-kafka/src/main/java/smoketest/kafka/ssl/SampleKafkaSslApplication.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2012-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package smoketest.kafka.ssl;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class SampleKafkaSslApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(SampleKafkaSslApplication.class, args);
+	}
+
+}

spring-boot-tests/spring-boot-smoke-tests/spring-boot-smoke-test-kafka/src/test/java/smoketest/kafka/ssl/SampleKafkaSslApplicationTests.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright 2012-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package smoketest.kafka.ssl;
+
+import java.io.File;
+import java.time.Duration;
+
+import org.awaitility.Awaitility;
+import org.junit.jupiter.api.Test;
+import org.testcontainers.containers.DockerComposeContainer;
+import org.testcontainers.containers.wait.strategy.Wait;
+import org.testcontainers.junit.jupiter.Container;
+import org.testcontainers.junit.jupiter.Testcontainers;
+import smoketest.kafka.Consumer;
+import smoketest.kafka.Producer;
+import smoketest.kafka.SampleMessage;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.hamcrest.Matchers.empty;
+import static org.hamcrest.Matchers.not;
+
+@Testcontainers
+@SpringBootTest(classes = { SampleKafkaSslApplication.class, Producer.class, Consumer.class },
+		properties = { "spring.kafka.security.protocol=SSL", "spring.kafka.bootstrap-servers=localhost:9093",
+				"spring.kafka.ssl.bundle=client",
+				"spring.ssl.bundle.jks.client.keystore.location=classpath:ssl/test-client.p12",
+				"spring.ssl.bundle.jks.client.keystore.password=password",
+				"spring.ssl.bundle.jks.client.truststore.location=classpath:ssl/test-ca.p12",
+				"spring.ssl.bundle.jks.client.truststore.password=password" })
+class SampleKafkaSslApplicationTests {
+
+	private static final File KAFKA_COMPOSE_FILE = new File("src/test/resources/docker-compose.yml");
+
+	private static final String KAFKA_COMPOSE_SERVICE = "kafka";
+
+	private static final int KAFKA_SSL_PORT = 9093;
+
+	@Container
+	public DockerComposeContainer<?> container = new DockerComposeContainer<>(KAFKA_COMPOSE_FILE)
+		.withExposedService(KAFKA_COMPOSE_SERVICE, KAFKA_SSL_PORT, Wait.forListeningPorts(KAFKA_SSL_PORT));
+
+	@Autowired
+	private Producer producer;
+
+	@Autowired
+	private Consumer consumer;
+
+	@Test
+	void testVanillaExchange() {
+		this.producer.send(new SampleMessage(1, "A simple test message"));
+
+		Awaitility.waitAtMost(Duration.ofSeconds(30)).until(this.consumer::getMessages, not(empty()));
+		assertThat(this.consumer.getMessages()).extracting("message").containsOnly("A simple test message");
+	}
+
+}

spring-boot-tests/spring-boot-smoke-tests/spring-boot-smoke-test-kafka/src/test/resources/docker-compose.yml

@@ -0,0 +1,30 @@
+---
+version: '2'
+services:
+  zookeeper:
+    image: confluentinc/cp-zookeeper:7.4.0
+    environment:
+      ZOOKEEPER_CLIENT_PORT: 2181
+      ZOOKEEPER_TICK_TIME: 2000
+
+  kafka:
+    image: confluentinc/cp-kafka:7.4.0
+    depends_on:
+      - zookeeper
+    ports:
+      - "9092:9092"
+      - "9093:9093"
+    environment:
+      KAFKA_BROKER_ID: 1
+      KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181
+      KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://localhost:9092,SSL://localhost:9093
+      KAFKA_AUTO_CREATE_TOPICS_ENABLE: 'true'
+      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
+      KAFKA_SSL_CLIENT_AUTH: "required"
+      KAFKA_SSL_KEYSTORE_FILENAME: '/certs/test-server.p12'
+      KAFKA_SSL_KEYSTORE_CREDENTIALS: '/certs/credentials'
+      KAFKA_SSL_KEY_CREDENTIALS: '/certs/credentials'
+      KAFKA_SSL_TRUSTSTORE_FILENAME: '/certs/test-ca.p12'
+      KAFKA_SSL_TRUSTSTORE_CREDENTIALS: '/certs/credentials'
+    volumes:
+      - ./ssl/:/etc/kafka/secrets/certs

spring-boot-tests/spring-boot-smoke-tests/spring-boot-smoke-test-kafka/src/test/resources/ssl/credentials

@@ -0,0 +1 @@
+password