KAFKA-12172 Migrate streams:examples module to JUnit 5 (#9857)

This PR includes following changes.
1. replace org.junit.Assert by org.junit.jupiter.api.Assertions
2. replace org.junit by org.junit.jupiter.api
3. replace Before by BeforeEach
4. replace After by AfterEach

Reviewers: Ismael Juma <ismael@confluent.io>

build.gradle

@@ -241,7 +241,7 @@ subprojects {
     }
   }
 
-  def shouldUseJUnit5 = ["tools", "raft", "log4j-appender"].contains(it.project.name)
+  def shouldUseJUnit5 = ["tools", "raft", "log4j-appender", "examples"].contains(it.project.name)
   def testLoggingEvents = ["passed", "skipped", "failed"]
   def testShowStandardStreams = false
   def testExceptionFormat = 'full'
@@ -1527,8 +1527,8 @@ project(':streams:examples') {
 
     testCompile project(':streams:test-utils')
     testCompile project(':clients').sourceSets.test.output // for org.apache.kafka.test.IntegrationTest
-    testCompile libs.junitJupiterApi
-    testCompile libs.junitVintageEngine
+    testCompile libs.junitJupiter
+    testCompile libs.hamcrest
   }
 
   javadoc {

streams/examples/src/test/java/org/apache/kafka/streams/examples/docs/DeveloperGuideTesting.java

@@ -32,9 +32,9 @@ import org.apache.kafka.streams.processor.api.Record;
 import org.apache.kafka.streams.state.KeyValueIterator;
 import org.apache.kafka.streams.state.KeyValueStore;
 import org.apache.kafka.streams.state.Stores;
-import org.junit.After;
-import org.junit.Before;
-import org.junit.Test;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 
 import java.time.Duration;
 import java.time.Instant;
@@ -57,7 +57,7 @@ public class DeveloperGuideTesting {
     private Serde<String> stringSerde = new Serdes.StringSerde();
     private Serde<Long> longSerde = new Serdes.LongSerde();
 
-    @Before
+    @BeforeEach
     public void setup() {
         final Topology topology = new Topology();
         topology.addSource("sourceProcessor", "input-topic");
@@ -85,7 +85,7 @@ public class DeveloperGuideTesting {
         store.put("a", 21L);
     }
 
-    @After
+    @AfterEach
     public void tearDown() {
         testDriver.close();
     }

streams/examples/src/test/java/org/apache/kafka/streams/examples/wordcount/WordCountDemoTest.java

@@ -26,9 +26,9 @@ import org.apache.kafka.streams.TopologyTestDriver;
 import org.apache.kafka.streams.TestInputTopic;
 import org.apache.kafka.streams.TestOutputTopic;
 import org.apache.kafka.test.TestUtils;
-import org.junit.After;
-import org.junit.Before;
-import org.junit.Test;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 
 import java.io.File;
 import java.io.IOException;
@@ -52,7 +52,7 @@ public class WordCountDemoTest {
     private TestInputTopic<String, String> inputTopic;
     private TestOutputTopic<String, Long> outputTopic;
 
-    @Before
+    @BeforeEach
     public void setup() throws IOException {
         final StreamsBuilder builder = new StreamsBuilder();
         //Create Actual Stream Processing pipeline
@@ -62,7 +62,7 @@ public class WordCountDemoTest {
         outputTopic = testDriver.createOutputTopic(WordCountDemo.OUTPUT_TOPIC, new StringDeserializer(), new LongDeserializer());
     }
 
-    @After
+    @AfterEach
     public void tearDown() {
         try {
             testDriver.close();

streams/examples/src/test/java/org/apache/kafka/streams/examples/wordcount/WordCountProcessorTest.java

@@ -22,14 +22,14 @@ import org.apache.kafka.streams.processor.api.Processor;
 import org.apache.kafka.streams.processor.api.Record;
 import org.apache.kafka.streams.state.KeyValueStore;
 import org.apache.kafka.streams.state.Stores;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 import java.util.Arrays;
 import java.util.List;
 
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.MatcherAssert.assertThat;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 /**
  * Demonstrate the use of {@link MockProcessorContext} for testing the {@link Processor} in the {@link WordCountProcessorDemo}.

streams/examples/src/test/java/org/apache/kafka/streams/examples/wordcount/WordCountTransformerTest.java

@@ -21,13 +21,13 @@ import org.apache.kafka.streams.kstream.Transformer;
 import org.apache.kafka.streams.processor.MockProcessorContext;
 import org.apache.kafka.streams.processor.StateStore;
 import org.apache.kafka.streams.state.StoreBuilder;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 import java.util.Iterator;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 /**
  * Demonstrate the use of {@link MockProcessorContext} for testing the {@link Transformer} in the {@link WordCountTransformerDemo}.