Use Awaitility

gradle.properties

@@ -10,4 +10,5 @@ junitVersion=5.11.4
 mockitoVersion=5.15.2
 assertJVersion=3.27.2
 log4jVersion=2.24.3
+awaitilityVersion=4.2.2
 org.gradle.jvmargs=-Xmx4096m

streams-bootstrap-cli/src/main/java/com/bakdata/kafka/KafkaApplication.java

@@ -1,7 +1,7 @@
 /*
  * MIT License
  *
- * Copyright (c) 2024 bakdata
+ * Copyright (c) 2025 bakdata
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -95,7 +95,7 @@ public abstract class KafkaApplication<R extends Runner, CR extends CleanUpRunne
     private Map<String, String> kafkaConfig = emptyMap();
 
     /**
-     * <p>This methods needs to be called in the executable custom application class inheriting from
+     * <p>This method needs to be called in the executable custom application class inheriting from
      * {@code KafkaApplication}.</p>
      * <p>This method calls System exit</p>
      *
@@ -109,7 +109,7 @@ public static void startApplication(final KafkaApplication<?, ?, ?, ?, ?, ?, ?>
     }
 
     /**
-     * <p>This methods needs to be called in the executable custom application class inheriting from
+     * <p>This method needs to be called in the executable custom application class inheriting from
      * {@code KafkaApplication}.</p>
      *
      * @param app An instance of the custom application class.

streams-bootstrap-cli/src/test/java/com/bakdata/kafka/CliTest.java

@@ -27,6 +27,7 @@
 import static com.bakdata.kafka.KafkaTest.POLL_TIMEOUT;
 import static com.bakdata.kafka.KafkaTest.newCluster;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.awaitility.Awaitility.await;
 
 import com.bakdata.kafka.SenderBuilder.SimpleProducerRecord;
 import com.ginsberg.junit.exit.ExpectSystemExitWithStatus;
@@ -46,8 +47,10 @@
 
 class CliTest {
 
-    private static void runApp(final KafkaStreamsApplication<?> app, final String... args) {
-        new Thread(() -> KafkaApplication.startApplication(app, args)).start();
+    private static Thread runApp(final KafkaStreamsApplication<?> app, final String... args) {
+        final Thread thread = new Thread(() -> KafkaApplication.startApplication(app, args));
+        thread.start();
+        return thread;
     }
 
     @Test
@@ -214,7 +217,7 @@ public SerdeConfig defaultSerializationConfig() {
 
     @Test
     @ExpectSystemExitWithStatus(1)
-    void shouldExitWithErrorInTopology() throws InterruptedException {
+    void shouldExitWithErrorInTopology() {
         final String input = "input";
         try (final KafkaContainer kafkaCluster = newCluster();
                 final KafkaStreamsApplication<?> app = new SimpleKafkaStreamsApplication<>(() -> new StreamsApp() {
@@ -238,7 +241,7 @@ public SerdeConfig defaultSerializationConfig() {
                 })) {
             kafkaCluster.start();
 
-            runApp(app,
+            final Thread thread = runApp(app,
                     "--bootstrap-server", kafkaCluster.getBootstrapServers(),
                     "--input-topics", input
             );
@@ -248,7 +251,7 @@ public SerdeConfig defaultSerializationConfig() {
                     .with(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class)
                     .with(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class)
                     .to(input, List.of(new SimpleProducerRecord<>("foo", "bar")));
-            Thread.sleep(Duration.ofSeconds(10).toMillis());
+            await("Thread is dead").atMost(Duration.ofSeconds(10L)).until(() -> !thread.isAlive());
         }
     }
 

streams-bootstrap-cli/src/test/java/com/bakdata/kafka/integration/RunProducerAppTest.java

@@ -38,7 +38,6 @@
 import com.bakdata.kafka.util.ImprovedAdminClient;
 import io.confluent.kafka.streams.serdes.avro.SpecificAvroDeserializer;
 import io.confluent.kafka.streams.serdes.avro.SpecificAvroSerializer;
-import java.time.Duration;
 import org.apache.kafka.clients.consumer.ConsumerConfig;
 import org.apache.kafka.clients.producer.Producer;
 import org.apache.kafka.clients.producer.ProducerRecord;
@@ -47,10 +46,9 @@
 import org.junit.jupiter.api.Test;
 
 class RunProducerAppTest extends KafkaTest {
-    private static final Duration TIMEOUT = Duration.ofSeconds(10);
 
     @Test
-    void shouldRunApp() throws InterruptedException {
+    void shouldRunApp() {
         final String output = "output";
         try (final KafkaProducerApplication<?> app = new SimpleKafkaProducerApplication<>(() -> new ProducerApp() {
             @Override
@@ -84,7 +82,6 @@ public SerializerConfig defaultSerializationConfig() {
                         assertThat(kv.value().getContent()).isEqualTo("bar");
                     });
             app.clean();
-            Thread.sleep(TIMEOUT.toMillis());
             try (final ImprovedAdminClient admin = testClient.admin()) {
                 assertThat(admin.getTopicClient().exists(app.getOutputTopic()))
                         .as("Output topic is deleted")

streams-bootstrap-cli/src/test/java/com/bakdata/kafka/integration/RunStreamsAppTest.java

@@ -39,10 +39,7 @@
 import org.apache.kafka.common.serialization.StringDeserializer;
 import org.apache.kafka.common.serialization.StringSerializer;
 import org.junit.jupiter.api.Test;
-import org.junit.jupiter.api.extension.ExtendWith;
-import org.mockito.junit.jupiter.MockitoExtension;
 
-@ExtendWith(MockitoExtension.class)
 class RunStreamsAppTest extends KafkaTest {
 
     @Test

streams-bootstrap-cli/src/test/java/com/bakdata/kafka/integration/StreamsCleanUpTest.java

@@ -33,7 +33,6 @@
 import com.bakdata.kafka.SimpleKafkaStreamsApplication;
 import com.bakdata.kafka.test_applications.WordCount;
 import com.bakdata.kafka.util.ImprovedAdminClient;
-import java.time.Duration;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
@@ -52,33 +51,15 @@
 import org.assertj.core.api.junit.jupiter.SoftAssertionsExtension;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
-import org.mockito.junit.jupiter.MockitoExtension;
-import org.mockito.junit.jupiter.MockitoSettings;
-import org.mockito.quality.Strictness;
 
 @Slf4j
 @ExtendWith(SoftAssertionsExtension.class)
-@ExtendWith(MockitoExtension.class)
-@MockitoSettings(strictness = Strictness.STRICT_STUBS)
 class StreamsCleanUpTest extends KafkaTest {
-    private static final Duration TIMEOUT = Duration.ofSeconds(10);
     @InjectSoftAssertions
     private SoftAssertions softly;
 
-    private static void runAppAndClose(final KafkaStreamsApplication<?> app) throws InterruptedException {
-        runApp(app);
-        app.stop();
-    }
-
-    private static void runApp(final KafkaStreamsApplication<?> app) throws InterruptedException {
-        // run in Thread because the application blocks indefinitely
-        new Thread(app).start();
-        // Wait until stream application has consumed all data
-        Thread.sleep(TIMEOUT.toMillis());
-    }
-
     @Test
-    void shouldClean() throws InterruptedException {
+    void shouldClean() {
         try (final KafkaStreamsApplication<?> app = this.createWordCountApplication()) {
             final KafkaTestClient testClient = this.newTestClient();
             testClient.createTopic(app.getOutputTopic());
@@ -98,8 +79,8 @@ void shouldClean() throws InterruptedException {
             );
             this.runAndAssertContent(expectedValues, "All entries are once in the input topic after the 1st run", app);
 
-            // Wait until all stream application are completely stopped before triggering cleanup
-            Thread.sleep(TIMEOUT.toMillis());
+            // Wait until all stream applications are completely stopped before triggering cleanup
+            this.awaitClosed(app.createExecutableApp());
             app.clean();
 
             try (final ImprovedAdminClient admin = testClient.admin()) {
@@ -114,7 +95,7 @@ void shouldClean() throws InterruptedException {
     }
 
     @Test
-    void shouldReset() throws InterruptedException {
+    void shouldReset() {
         try (final KafkaStreamsApplication<?> app = this.createWordCountApplication()) {
             final KafkaTestClient testClient = this.newTestClient();
             testClient.createTopic(app.getOutputTopic());
@@ -134,8 +115,8 @@ void shouldReset() throws InterruptedException {
             );
             this.runAndAssertContent(expectedValues, "All entries are once in the input topic after the 1st run", app);
 
-            // Wait until all stream application are completely stopped before triggering cleanup
-            Thread.sleep(TIMEOUT.toMillis());
+            // Wait until all stream applications are completely stopped before triggering cleanup
+            this.awaitClosed(app.createExecutableApp());
             app.reset();
 
             try (final ImprovedAdminClient admin = testClient.admin()) {
@@ -152,21 +133,31 @@ void shouldReset() throws InterruptedException {
     }
 
     @Test
-    void shouldCallClose() throws InterruptedException {
+    void shouldCallClose() {
         try (final CloseFlagApp app = this.createCloseFlagApplication()) {
             this.newTestClient().createTopic(app.getInputTopics().get(0));
-            Thread.sleep(TIMEOUT.toMillis());
             this.softly.assertThat(app.isClosed()).isFalse();
             this.softly.assertThat(app.isAppClosed()).isFalse();
             app.clean();
             this.softly.assertThat(app.isAppClosed()).isTrue();
             app.setAppClosed(false);
-            Thread.sleep(TIMEOUT.toMillis());
             app.reset();
             this.softly.assertThat(app.isAppClosed()).isTrue();
         }
     }
 
+    private void runAppAndClose(final KafkaStreamsApplication<?> app) {
+        this.runApp(app);
+        app.stop();
+    }
+
+    private void runApp(final KafkaStreamsApplication<?> app) {
+        // run in Thread because the application blocks indefinitely
+        new Thread(app).start();
+        // Wait until stream application has consumed all data
+        this.awaitProcessing(app.createExecutableApp());
+    }
+
     private CloseFlagApp createCloseFlagApplication() {
         final CloseFlagApp app = new CloseFlagApp();
         app.setInputTopics(List.of("input"));
@@ -185,9 +176,8 @@ private List<KeyValue<String, Long>> readOutputTopic(final String outputTopic) {
     }
 
     private void runAndAssertContent(final Iterable<? extends KeyValue<String, Long>> expectedValues,
-            final String description, final KafkaStreamsApplication<?> app)
-            throws InterruptedException {
-        runAppAndClose(app);
+            final String description, final KafkaStreamsApplication<?> app) {
+        this.runAppAndClose(app);
 
         final List<KeyValue<String, Long>> output = this.readOutputTopic(app.getOutputTopic());
         this.softly.assertThat(output)

streams-bootstrap-core/build.gradle.kts

@@ -38,6 +38,8 @@ dependencies {
     testImplementation(group = "io.confluent", name = "kafka-streams-avro-serde", version = confluentVersion)
     val log4jVersion: String by project
     testImplementation(group = "org.apache.logging.log4j", name = "log4j-slf4j2-impl", version = log4jVersion)
+    val awaitilityVersion: String by project
+    testFixturesApi(group = "org.awaitility", name = "awaitility", version = awaitilityVersion)
 }
 
 tasks.withType<Test> {

streams-bootstrap-core/src/main/java/com/bakdata/kafka/util/ConsumerGroupClient.java

@@ -36,7 +36,10 @@
 import lombok.extern.slf4j.Slf4j;
 import org.apache.kafka.clients.admin.Admin;
 import org.apache.kafka.clients.admin.AdminClient;
+import org.apache.kafka.clients.admin.ConsumerGroupDescription;
 import org.apache.kafka.clients.admin.ConsumerGroupListing;
+import org.apache.kafka.clients.consumer.OffsetAndMetadata;
+import org.apache.kafka.common.TopicPartition;
 import org.apache.kafka.common.errors.GroupIdNotFoundException;
 
 /**
@@ -68,6 +71,14 @@ private static KafkaAdminException failedToListGroups(final Throwable ex) {
         return new KafkaAdminException("Failed to list consumer groups", ex);
     }
 
+    private static KafkaAdminException failedToListOffsets(final String groupName, final Throwable ex) {
+        return new KafkaAdminException("Failed to list offsets for consumer group" + groupName, ex);
+    }
+
+    private static KafkaAdminException failedToDescribeGroup(final String groupName, final Throwable ex) {
+        return new KafkaAdminException("Failed to describe consumer group" + groupName, ex);
+    }
+
     /**
      * Delete a consumer group.
      *
@@ -93,6 +104,63 @@ public void deleteConsumerGroup(final String groupName) {
         }
     }
 
+    /**
+     * Describe a consumer group.
+     *
+     * @param groupName the consumer group name
+     * @return consumer group description
+     */
+    public ConsumerGroupDescription describe(final String groupName) {
+        log.info("Describing consumer group '{}'", groupName);
+        try {
+            final ConsumerGroupDescription description =
+                    this.adminClient.describeConsumerGroups(List.of(groupName))
+                            .all()
+                            .get(this.timeout.toSeconds(), TimeUnit.SECONDS)
+                            .get(groupName);
+            log.info("Described consumer group '{}'", groupName);
+            return description;
+        } catch (final InterruptedException ex) {
+            Thread.currentThread().interrupt();
+            throw failedToDescribeGroup(groupName, ex);
+        } catch (final ExecutionException ex) {
+            if (ex.getCause() instanceof RuntimeException) {
+                throw (RuntimeException) ex.getCause();
+            }
+            throw failedToDescribeGroup(groupName, ex);
+        } catch (final TimeoutException ex) {
+            throw failedToDescribeGroup(groupName, ex);
+        }
+    }
+
+    /**
+     * List offsets for a consumer group.
+     *
+     * @param groupName the consumer group name
+     * @return consumer group offsets
+     */
+    public Map<TopicPartition, OffsetAndMetadata> listOffsets(final String groupName) {
+        log.info("Listing offsets for consumer group '{}'", groupName);
+        try {
+            final Map<TopicPartition, OffsetAndMetadata> offsets =
+                    this.adminClient.listConsumerGroupOffsets(groupName)
+                            .partitionsToOffsetAndMetadata(groupName)
+                            .get(this.timeout.toSeconds(), TimeUnit.SECONDS);
+            log.info("Listed offsets for consumer group '{}'", groupName);
+            return offsets;
+        } catch (final InterruptedException ex) {
+            Thread.currentThread().interrupt();
+            throw failedToListOffsets(groupName, ex);
+        } catch (final ExecutionException ex) {
+            if (ex.getCause() instanceof RuntimeException) {
+                throw (RuntimeException) ex.getCause();
+            }
+            throw failedToListOffsets(groupName, ex);
+        } catch (final TimeoutException ex) {
+            throw failedToListOffsets(groupName, ex);
+        }
+    }
+
     @Override
     public void close() {
         this.adminClient.close();