From 330b7238f03cdfafd72f9980ce0f019c46b02afe Mon Sep 17 00:00:00 2001
From: Kai Moritz <kai@juplo.de>
Date: Sun, 12 Jun 2022 11:57:33 +0200
Subject: [PATCH] =?utf8?q?Testfall,=20der=20die=20API=20aufruft=20und=20pr?=
 =?utf8?q?=C3=BCft,=20ob=20Nachrichten=20versendet=20werden?=
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* Der Testfall verwendet `spring-kafka` als Abhängigkeit mit dem Scope
  `test`.
* Dies zeigt ein nicht zu unterschätzendes Anwendungsfeld für Spring
  Kafka, seblst wenn das eigentliche Projekt gar nicht auf Spring Kafka
  aufsetzt: Einfache Implementierung von Integration-Tests.
---
 pom.xml                                       | 15 ++++
 .../java/de/juplo/kafka/ApplicationTests.java | 86 +++++++++++++++++++
 2 files changed, 101 insertions(+)
 create mode 100644 src/test/java/de/juplo/kafka/ApplicationTests.java

diff --git a/pom.xml b/pom.xml
index d02cfc0..46a8165 100644
--- a/pom.xml
+++ b/pom.xml
@@ -43,6 +43,21 @@
       <artifactId>spring-boot-starter-test</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.springframework.kafka</groupId>
+      <artifactId>spring-kafka</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.springframework.kafka</groupId>
+      <artifactId>spring-kafka-test</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.awaitility</groupId>
+      <artifactId>awaitility</artifactId>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
   <build>
diff --git a/src/test/java/de/juplo/kafka/ApplicationTests.java b/src/test/java/de/juplo/kafka/ApplicationTests.java
new file mode 100644
index 0000000..cf70c81
--- /dev/null
+++ b/src/test/java/de/juplo/kafka/ApplicationTests.java
@@ -0,0 +1,86 @@
+package de.juplo.kafka;
+
+import lombok.extern.slf4j.Slf4j;
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.junit.jupiter.api.*;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.TestConfiguration;
+import org.springframework.context.annotation.Bean;
+import org.springframework.kafka.annotation.KafkaListener;
+import org.springframework.kafka.test.context.EmbeddedKafka;
+import org.springframework.test.web.servlet.MockMvc;
+
+import java.time.Duration;
+import java.util.LinkedList;
+import java.util.List;
+
+import static de.juplo.kafka.ApplicationTests.PARTITIONS;
+import static de.juplo.kafka.ApplicationTests.TOPIC;
+import static org.awaitility.Awaitility.*;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.put;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+
+@SpringBootTest(
+		properties = {
+				"spring.kafka.consumer.bootstrap-servers=${spring.embedded.kafka.brokers}",
+				"producer.bootstrap-server=${spring.embedded.kafka.brokers}",
+				"producer.topic=" + TOPIC})
+@AutoConfigureMockMvc
+@EmbeddedKafka(topics = TOPIC, partitions = PARTITIONS)
+@Slf4j
+public class ApplicationTests
+{
+	static final String TOPIC = "FOO";
+	static final int PARTITIONS = 10;
+
+	@Autowired
+	MockMvc mockMvc;
+	@Autowired
+	Consumer consumer;
+
+
+	@BeforeEach
+	public void clear()
+	{
+		consumer.received.clear();
+	}
+
+
+	@Test
+	void testSendMessage() throws Exception
+	{
+		mockMvc
+				.perform(post("/peter").content("Hallo Welt!"))
+				.andExpect(status().isOk());
+		await("Message was send")
+				.atMost(Duration.ofSeconds(5))
+				.until(() -> consumer.received.size() == 1);
+	}
+
+
+	static class Consumer
+	{
+		final List<ConsumerRecord<String, String>> received = new LinkedList<>();
+
+		@KafkaListener(groupId = "TEST", topics = TOPIC)
+		public void receive(ConsumerRecord<String, String> record)
+		{
+			log.debug("Received message: {}", record);
+			received.add(record);
+		}
+	}
+
+	@TestConfiguration
+	static class Configuration
+	{
+		@Bean
+		Consumer consumer()
+		{
+			return new Consumer();
+		}
+	}
+}
-- 
2.20.1