Add integration test for kafka-streams wordcount sample

kafka-streams-samples/kafka-streams-word-count/pom.xml

@@ -31,6 +31,11 @@
 			<artifactId>spring-boot-starter-test</artifactId>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.kafka</groupId>
+			<artifactId>spring-kafka-test</artifactId>
+            <scope>test</scope>
+		</dependency>
 	</dependencies>
 
     <build>

kafka-streams-samples/kafka-streams-word-count/src/test/java/kafka/streams/word/count/KafkaStreamsWordCountApplicationTests.java

@@ -1,18 +1,94 @@
+/*
+ * Copyright 2019 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
+ *
+ *      http://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 kafka.streams.word.count;
 
-import org.junit.Ignore;
+import org.apache.kafka.clients.consumer.Consumer;
+import org.apache.kafka.clients.consumer.ConsumerConfig;
+import org.apache.kafka.clients.consumer.ConsumerRecords;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.ClassRule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.kafka.core.DefaultKafkaConsumerFactory;
+import org.springframework.kafka.core.DefaultKafkaProducerFactory;
+import org.springframework.kafka.core.KafkaTemplate;
+import org.springframework.kafka.test.EmbeddedKafkaBroker;
+import org.springframework.kafka.test.rule.EmbeddedKafkaRule;
+import org.springframework.kafka.test.utils.KafkaTestUtils;
 import org.springframework.test.context.junit4.SpringRunner;
 
+import java.util.Map;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
 @RunWith(SpringRunner.class)
-@SpringBootTest
+@SpringBootTest(
+		webEnvironment = SpringBootTest.WebEnvironment.NONE,
+		properties = {"server.port=0",
+		"spring.jmx.enabled=false",
+		"spring.cloud.stream.bindings.input.destination=words",
+		"spring.cloud.stream.bindings.output.destination=counts",
+		"spring.cloud.stream.bindings.output.contentType=application/json",
+		"spring.cloud.stream.kafka.streams.default.consumer.application-id=basic-word-count",
+		"spring.cloud.stream.kafka.streams.binder.configuration.commit.interval.ms=1000",
+		"spring.cloud.stream.kafka.streams.binder.configuration.default.key.serde=org.apache.kafka.common.serialization.Serdes$StringSerde",
+		"spring.cloud.stream.kafka.streams.binder.configuration.default.value.serde=org.apache.kafka.common.serialization.Serdes$StringSerde"})
 public class KafkaStreamsWordCountApplicationTests {
 
+	@ClassRule
+	public static EmbeddedKafkaRule embeddedKafkaRule = new EmbeddedKafkaRule(1, true, "words", "counts");
+
+	private static EmbeddedKafkaBroker embeddedKafka = embeddedKafkaRule.getEmbeddedKafka();
+
+	private static Consumer<String, String> consumer;
+
+	@BeforeClass
+	public static void setUp() throws Exception {
+		Map<String, Object> consumerProps = KafkaTestUtils.consumerProps("group", "false", embeddedKafka);
+		consumerProps.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
+		DefaultKafkaConsumerFactory<String, String> cf = new DefaultKafkaConsumerFactory<>(consumerProps);
+		consumer = cf.createConsumer();
+		embeddedKafka.consumeFromAnEmbeddedTopic(consumer, "counts");
+
+		System.setProperty("spring.cloud.stream.kafka.streams.binder.brokers", embeddedKafka.getBrokersAsString());
+	}
+
+	@AfterClass
+	public static void tearDown() {
+		consumer.close();
+		System.clearProperty("spring.cloud.stream.kafka.streams.binder.brokers");
+	}
+
 	@Test
-	@Ignore
-	public void contextLoads() {
+	public void testKstreamWordCountWithApplicationIdSpecifiedAtDefaultConsumer() throws Exception {
+		Map<String, Object> senderProps = KafkaTestUtils.producerProps(embeddedKafka);
+		DefaultKafkaProducerFactory<Integer, String> pf = new DefaultKafkaProducerFactory<>(senderProps);
+		try {
+			KafkaTemplate<Integer, String> template = new KafkaTemplate<>(pf, true);
+			template.setDefaultTopic("words");
+			template.sendDefault("foobar");
+			ConsumerRecords<String, String> cr = KafkaTestUtils.getRecords(consumer);
+			assertThat(cr.count()).isGreaterThanOrEqualTo(1);
+		}
+		finally {
+			pf.destroy();
+		}
 	}
 
 }