Update testing docs for 4.0.0 with the updates in EmbeddedKafka

* Update testing docs for 4.0.0 with the updates in EmbeddedKafka

Signed-off-by: Soby Chacko <[email protected]>

* Addressing PR review

---------

Signed-off-by: Soby Chacko <[email protected]>

Author: sobychacko

spring-kafka-docs/src/main/antora/modules/ROOT/pages/quick-tour.adoc

@@ -58,8 +58,8 @@ However, the quickest way to get started is to use https://start.spring.io[start
 
 This quick tour works with the following versions:
 
-* Apache Kafka Clients 3.7.x
-* Spring Framework 6.1.x
+* Apache Kafka Clients 4.0.x
+* Spring Framework 7.0.0
 * Minimum Java version: 17
 
 [[getting-started]]

spring-kafka-docs/src/main/antora/modules/ROOT/pages/testing.adoc

@@ -6,10 +6,9 @@ The `spring-kafka-test` jar contains some useful utilities to assist with testin
 [[ekb]]
 == Embedded Kafka Broker
 
-Two implementations are provided:
+Since Kafka 4.0 has fully transitioned to KRaft mode, only the `EmbeddedKafkaKraftBroker` implementation is now available:
 
-* `EmbeddedKafkaZKBroker` - legacy implementation which starts an embedded `Zookeeper` instance (which is still the default when using `EmbeddedKafka`).
-* `EmbeddedKafkaKraftBroker` - uses `Kraft` instead of `Zookeeper` in combined controller and broker modes (since 3.1).
+* `EmbeddedKafkaKraftBroker` - uses `Kraft` in combined controller and broker modes.
 
 There are several techniques to configure the broker as discussed in the following sections.
 
@@ -22,7 +21,7 @@ Refer to its javadoc:org.springframework.kafka.test.utils.KafkaTestUtils[Javadoc
 [[junit]]
 == JUnit
 
-`org.springframework.kafka.test.utils.KafkaTestUtils` also provides some static methods to set up producer and consumer properties.
+`org.springframework.kafka.test.utils.KafkaTestUtils` provides some static methods to set up producer and consumer properties.
 The following listing shows those method signatures:
 
 [source, java]
@@ -57,32 +56,8 @@ If this is not possible for some reason, note that the `consumeFromEmbeddedTopic
 Since it does not have access to the consumer properties, you must use the overloaded method that takes a `seekToEnd` boolean parameter to seek to the end instead of the beginning.
 ====
 
-A JUnit 4 `@Rule` wrapper for the `EmbeddedKafkaZKBroker` is provided to create an embedded Kafka and an embedded Zookeeper server.
-(See xref:testing.adoc#embedded-kafka-annotation[@EmbeddedKafka Annotation] for information about using `@EmbeddedKafka` with JUnit 5).
-The following listing shows the signatures of those methods:
-
-[source, java]
-----
-/**
- * Create embedded Kafka brokers.
- * @param count the number of brokers.
- * @param controlledShutdown passed into TestUtils.createBrokerConfig.
- * @param topics the topics to create (2 partitions per).
- */
-public EmbeddedKafkaRule(int count, boolean controlledShutdown, String... topics) { ... }
-
-/**
- *
- * Create embedded Kafka brokers.
- * @param count the number of brokers.
- * @param controlledShutdown passed into TestUtils.createBrokerConfig.
- * @param partitions partitions per topic.
- * @param topics the topics to create.
- */
-public EmbeddedKafkaRule(int count, boolean controlledShutdown, int partitions, String... topics) { ... }
-----
-
-NOTE: The `EmbeddedKafkaKraftBroker` is not supported with JUnit4.
+NOTE: The `EmbeddedKafkaRule` JUnit 4 rule has been removed in version 4.0.
+For JUnit 4, you should use the `EmbeddedKafkaKraftBroker` directly or migrate to JUnit 5 with the `@EmbeddedKafka` annotation.
 
 The `EmbeddedKafkaBroker` class has a utility method that lets you consume for all the topics it created.
 The following example shows how to use it:
@@ -127,8 +102,8 @@ ConsumerRecord<Integer, String> received = KafkaTestUtils.getSingleRecord(consum
 ...
 ----
 
-When the embedded Kafka and embedded Zookeeper server are started by the `EmbeddedKafkaBroker`, a system property named `spring.embedded.kafka.brokers` is set to the address of the Kafka brokers and a system property named `spring.embedded.zookeeper.connect` is set to the address of Zookeeper.
-Convenient constants (`EmbeddedKafkaBroker.SPRING_EMBEDDED_KAFKA_BROKERS` and `EmbeddedKafkaBroker.SPRING_EMBEDDED_ZOOKEEPER_CONNECT`) are provided for this property.
+When the embedded Kafka broker is started by the `EmbeddedKafkaBroker`, a system property named `spring.embedded.kafka.brokers` is set to the address of the Kafka brokers.
+Convenient constants (`EmbeddedKafkaBroker.SPRING_EMBEDDED_KAFKA_BROKERS`) are provided for this property.
 
 Instead of default `spring.embedded.kafka.brokers` system property, the address of the Kafka brokers can be exposed to any arbitrary and convenient property.
 For this purpose a `spring.embedded.kafka.brokers.property` (`EmbeddedKafkaBroker.BROKER_LIST_PROPERTY`) system property can be set before starting an embedded Kafka.
@@ -227,8 +202,7 @@ In addition, these properties can be provided:
 - `spring.kafka.embedded.ports` - ports (comma-separated value) for every Kafka broker to start, `0` if random port is preferred; the number of values must be equal to the `count` mentioned above;
 - `spring.kafka.embedded.topics` - topics (comma-separated value) to create in the started Kafka cluster;
 - `spring.kafka.embedded.partitions` - number of partitions to provision for the created topics;
-- `spring.kafka.embedded.broker.properties.location` - the location of the file for additional Kafka broker configuration properties; the value of this property must follow the Spring resource abstraction pattern;
-- `spring.kafka.embedded.kraft` - default false, when true, use an `EmbeddedKafkaKraftBroker` instead of an `EmbeddedKafkaZKBroker`.
+- `spring.kafka.embedded.broker.properties.location` - the location of the file for additional Kafka broker configuration properties; the value of this property must follow the Spring resource abstraction pattern.
 
 Essentially these properties mimic some of the `@EmbeddedKafka` attributes.
 
@@ -244,7 +218,7 @@ If you wish to use the embedded broker and are NOT using JUnit, you may wish to
 
 [[embedded-kafka-annotation]]
 == `@EmbeddedKafka` Annotation
-We generally recommend that you use the rule as a `@ClassRule` to avoid starting and stopping the broker between tests (and use a different topic for each test).
+We generally recommend that you use a single broker instance to avoid starting and stopping the broker between tests (and use a different topic for each test).
 Starting with version 2.0, if you use Spring's test application context caching, you can also declare a `EmbeddedKafkaBroker` bean, so a single broker can be used across multiple test classes.
 For convenience, we provide a test class-level annotation called `@EmbeddedKafka` to register the `EmbeddedKafkaBroker` bean.
 The following example shows how to use it:
@@ -295,7 +269,7 @@ public class KafkaStreamsTests {
 
 Starting with version 2.2.4, you can also use the `@EmbeddedKafka` annotation to specify the Kafka ports property.
 
-Starting with version 3.2, set the `kraft` property to `true` to use an `EmbeddedKafkaKraftBroker` instead of an `EmbeddedKafkaZKBroker`.
+NOTE: As of version 4.0, all ZooKeeper-related properties have been removed from the `@EmbeddedKafka` annotation since Kafka 4.0 uses KRaft exclusively.
 
 The following example sets the `topics`, `brokerProperties`, and `brokerPropertiesLocation` attributes of `@EmbeddedKafka` support property placeholder resolutions:
 
@@ -550,17 +524,20 @@ The following example brings together most of the topics covered in this chapter
 
 [source, java]
 ----
+@EmbeddedKafka(topics = KafkaTemplateTests.TEMPLATE_TOPIC)
 public class KafkaTemplateTests {
 
-    private static final String TEMPLATE_TOPIC = "templateTopic";
+    public static final String TEMPLATE_TOPIC = "templateTopic";
 
-    @ClassRule
-    public static EmbeddedKafkaRule embeddedKafka = new EmbeddedKafkaRule(1, true, TEMPLATE_TOPIC);
+    @BeforeAll
+	public static void setUp() {
+		embeddedKafka = EmbeddedKafkaCondition.getBroker();
+	}
 
     @Test
     public void testTemplate() throws Exception {
         Map<String, Object> consumerProps = KafkaTestUtils.consumerProps("testT", "false",
-            embeddedKafka.getEmbeddedKafka());
+            embeddedKafka);
         DefaultKafkaConsumerFactory<Integer, String> cf =
                             new DefaultKafkaConsumerFactory<>(consumerProps);
         ContainerProperties containerProperties = new ContainerProperties(TEMPLATE_TOPIC);
@@ -579,9 +556,9 @@ public class KafkaTemplateTests {
         container.setBeanName("templateTests");
         container.start();
         ContainerTestUtils.waitForAssignment(container,
-                            embeddedKafka.getEmbeddedKafka().getPartitionsPerTopic());
+                            embeddedKafka.getPartitionsPerTopic());
         Map<String, Object> producerProps =
-                            KafkaTestUtils.producerProps(embeddedKafka.getEmbeddedKafka());
+                            KafkaTestUtils.producerProps(embeddedKafka);
         ProducerFactory<Integer, String> pf =
                             new DefaultKafkaProducerFactory<>(producerProps);
         KafkaTemplate<Integer, String> template = new KafkaTemplate<>(pf);
@@ -599,7 +576,6 @@ public class KafkaTemplateTests {
         assertThat(received, hasPartition(0));
         assertThat(received, hasValue("baz"));
     }
-
 }
 ----