fix: Fix test stability issues

polling-publisher/polling-service/src/main/java/com/iluwatar/polling/App.java

@@ -40,6 +40,11 @@ public class App {
    * @param args command line args.
    */
   public static void main(String[] args) {
-    SpringApplication.run(App.class, args);
+    var context = SpringApplication.run(App.class, args);
+    if (args.length > 0 && "test".equals(args[0])) {
+      // Close the context immediately during tests to prevent Tomcat/background threads from
+      // hanging the JVM
+      context.close();
+    }
   }
 }

polling-publisher/polling-service/src/main/java/com/iluwatar/polling/DataSourceService.java

@@ -44,9 +44,22 @@ public class DataSourceService {
   private final ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor();
 
   /** Constructor & Scheduler to push random data. */
+  @org.springframework.beans.factory.annotation.Autowired
   public DataSourceService(DataRepository repository) {
+    this(repository, true);
+  }
+
+  /**
+   * Constructor with option to start the scheduler.
+   *
+   * @param repository the data repository
+   * @param startScheduler true to start the data generation scheduler
+   */
+  public DataSourceService(DataRepository repository, boolean startScheduler) {
     this.repository = repository;
-    scheduleDataGeneration();
+    if (startScheduler) {
+      scheduleDataGeneration();
+    }
   }
 
   private void scheduleDataGeneration() {
@@ -78,4 +91,9 @@ public class DataSourceService {
   public Map<Integer, String> getAllData() {
     return repository.findAll();
   }
+
+  @javax.annotation.PreDestroy
+  public void shutdown() {
+    scheduler.shutdown();
+  }
 }

polling-publisher/polling-service/src/test/java/com/iluwatar/polling/AppTest.java

@@ -28,12 +28,16 @@ import static org.junit.jupiter.api.Assertions.*;
 
 import org.junit.jupiter.api.Test;
 import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.kafka.test.context.EmbeddedKafka;
 
 @SpringBootTest
+@EmbeddedKafka(
+    partitions = 1,
+    topics = {"updates", "API"})
 public class AppTest {
 
   @Test
   void polling() {
-    assertDoesNotThrow(() -> App.main(new String[] {}));
+    assertDoesNotThrow(() -> App.main(new String[] {"test"}));
   }
 }

polling-publisher/polling-service/src/test/java/com/iluwatar/polling/DataSourceServiceTest.java

@@ -38,7 +38,7 @@ public class DataSourceServiceTest {
   @BeforeEach
   void setUp() {
     repository = new DataRepository();
-    service = new DataSourceService(repository);
+    service = new DataSourceService(repository, false);
   }
 
   @Test
@@ -77,8 +77,8 @@ public class DataSourceServiceTest {
 
     Map<Integer, String> result1 = service.getAllData();
 
-    assertEquals(size + 2, result.size(), "Should return all stored data.");
-    assertEquals("First", result.get(1), "Value for key 1 should be 'First'.");
-    assertEquals("Second", result.get(2), "Value for key 2 should be 'Second'.");
+    assertEquals(size + 2, result1.size(), "Should return all stored data.");
+    assertEquals("First", result1.get(1), "Value for key 1 should be 'First'.");
+    assertEquals("Second", result1.get(2), "Value for key 2 should be 'Second'.");
   }
 }

polling-publisher/subscriber-service/src/main/java/com/iluwatar/subscriber/App.java

@@ -32,6 +32,11 @@ import org.springframework.boot.autoconfigure.SpringBootApplication;
 @SpringBootApplication
 public class App {
   public static void main(String[] args) {
-    SpringApplication.run(App.class, args);
+    var context = SpringApplication.run(App.class, args);
+    if (args.length > 0 && "test".equals(args[0])) {
+      // Close the context immediately during tests to prevent Tomcat/background threads from
+      // hanging the JVM
+      context.close();
+    }
   }
 }

polling-publisher/subscriber-service/src/test/java/com/iluwatar/subscriber/AppTest.java

@@ -29,12 +29,16 @@ import static org.junit.jupiter.api.Assertions.*;
 
 import org.junit.jupiter.api.Test;
 import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.kafka.test.context.EmbeddedKafka;
 
 @SpringBootTest
+@EmbeddedKafka(
+    partitions = 1,
+    topics = {"updates", "API"})
 public class AppTest {
 
   @Test
   void subscriber() {
-    assertDoesNotThrow(() -> App.main(new String[] {}));
+    assertDoesNotThrow(() -> App.main(new String[] {"test"}));
   }
 }