Migrate all Java unit tests from JUnit 4 to JUnit 5

Replace @ClassRule/@rule with @RegisterExtension, remove JUnitSuite
base class, migrate Assert to Assertions, convert @test(expected=...)
to assertThrows(). Add thread-safe synchronized lifecycle methods to
PekkoJUnit5ActorSystemResource.

204 files changed across actor-tests, actor-typed-tests, stream-tests,
docs, coordination, cluster-tools, persistence-query, and
actor-testkit-typed modules.

Author: He-Pin

actor-testkit-typed/src/test/java/jdocs/org/apache/pekko/actor/testkit/typed/javadsl/AsyncTestingExampleTest.java

@@ -20,28 +20,32 @@
 import org.apache.pekko.actor.typed.javadsl.Behaviors;
 // #test-header
 import org.apache.pekko.actor.testkit.typed.javadsl.ActorTestKit;
+import org.apache.pekko.actor.testkit.typed.javadsl.JUnit5TestKitBuilder;
+import org.apache.pekko.actor.testkit.typed.javadsl.TestKitJUnit5Extension;
+import org.apache.pekko.actor.testkit.typed.javadsl.LogCapturingExtension;
 
 // #test-header
 import org.apache.pekko.actor.testkit.typed.javadsl.TestProbe;
-import org.junit.AfterClass;
-import org.junit.Test;
-import org.scalatestplus.junit.JUnitSuite;
+import org.apache.pekko.actor.testkit.typed.annotations.JUnit5TestKit;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
 
 import java.time.Duration;
 import java.util.concurrent.CompletionStage;
 import java.util.stream.IntStream;
 
 import java.util.Objects;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 // #test-header
+@ExtendWith({TestKitJUnit5Extension.class, LogCapturingExtension.class})
 public class AsyncTestingExampleTest
     // #test-header
-    extends JUnitSuite
+
 // #test-header
 {
-  static final ActorTestKit testKit = ActorTestKit.create();
+  @JUnit5TestKit public ActorTestKit testKit = new JUnit5TestKitBuilder().build();
   // #test-header
 
   // #under-test
@@ -128,10 +132,7 @@ private CompletionStage<Integer> publish(int i) {
   // #under-test-2
 
   // #test-shutdown
-  @AfterClass
-  public static void cleanup() {
-    testKit.shutdownTestKit();
-  }
+  // Test cleanup is automatically handled by JUnit 5 extension
   // #test-shutdown
 
   @Test
@@ -202,7 +203,7 @@ public void testObserveMockedBehavior() {
 
   @Test
   public void systemNameShouldComeFromTestClass() {
-    assertEquals(testKit.system().name(), "AsyncTestingExampleTest");
+    assertEquals("AsyncTestingExampleTest", testKit.system().name());
   }
   // #test-header
 }

actor-testkit-typed/src/test/java/jdocs/org/apache/pekko/actor/testkit/typed/javadsl/JunitIntegrationExampleTest.java

@@ -15,24 +15,23 @@
 
 import static jdocs.org.apache.pekko.actor.testkit.typed.javadsl.AsyncTestingExampleTest.Echo;
 
-import org.apache.pekko.actor.testkit.typed.javadsl.LogCapturing;
-import org.junit.Rule;
+import org.apache.pekko.actor.testkit.typed.javadsl.LogCapturingExtension;
 
 // #junit-integration
-import org.apache.pekko.actor.testkit.typed.javadsl.TestKitJunitResource;
+import org.apache.pekko.actor.testkit.typed.javadsl.ActorTestKit;
+import org.apache.pekko.actor.testkit.typed.javadsl.JUnit5TestKitBuilder;
+import org.apache.pekko.actor.testkit.typed.javadsl.TestKitJUnit5Extension;
 import org.apache.pekko.actor.testkit.typed.javadsl.TestProbe;
+import org.apache.pekko.actor.testkit.typed.annotations.JUnit5TestKit;
 import org.apache.pekko.actor.typed.ActorRef;
-import org.junit.ClassRule;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
 
+@ExtendWith(TestKitJUnit5Extension.class)
+@ExtendWith(LogCapturingExtension.class)
 public class JunitIntegrationExampleTest {
 
-  @ClassRule public static final TestKitJunitResource testKit = new TestKitJunitResource();
-
-  // #junit-integration
-  // this is shown in LogCapturingExampleTest
-  @Rule public final LogCapturing logCapturing = new LogCapturing();
-  // #junit-integration
+  @JUnit5TestKit public ActorTestKit testKit = new JUnit5TestKitBuilder().build();
 
   @Test
   public void testSomething() {

actor-testkit-typed/src/test/java/jdocs/org/apache/pekko/actor/testkit/typed/javadsl/LogCapturingExampleTest.java

@@ -16,19 +16,21 @@
 import static jdocs.org.apache.pekko.actor.testkit.typed.javadsl.AsyncTestingExampleTest.*;
 
 // #log-capturing
-import org.apache.pekko.actor.testkit.typed.javadsl.LogCapturing;
-import org.apache.pekko.actor.testkit.typed.javadsl.TestKitJunitResource;
+import org.apache.pekko.actor.testkit.typed.javadsl.LogCapturingExtension;
+import org.apache.pekko.actor.testkit.typed.javadsl.ActorTestKit;
+import org.apache.pekko.actor.testkit.typed.javadsl.JUnit5TestKitBuilder;
+import org.apache.pekko.actor.testkit.typed.javadsl.TestKitJUnit5Extension;
 import org.apache.pekko.actor.testkit.typed.javadsl.TestProbe;
+import org.apache.pekko.actor.testkit.typed.annotations.JUnit5TestKit;
 import org.apache.pekko.actor.typed.ActorRef;
-import org.junit.ClassRule;
-import org.junit.Rule;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
 
+@ExtendWith(TestKitJUnit5Extension.class)
+@ExtendWith(LogCapturingExtension.class)
 public class LogCapturingExampleTest {
 
-  @ClassRule public static final TestKitJunitResource testKit = new TestKitJunitResource();
-
-  @Rule public final LogCapturing logCapturing = new LogCapturing();
+  @JUnit5TestKit public ActorTestKit testKit = new JUnit5TestKitBuilder().build();
 
   @Test
   public void testSomething() {

actor-testkit-typed/src/test/java/jdocs/org/apache/pekko/actor/testkit/typed/javadsl/ManualTimerExampleTest.java

@@ -16,23 +16,21 @@
 // #manual-scheduling-simple
 
 import java.time.Duration;
-import org.apache.pekko.actor.testkit.typed.javadsl.LogCapturing;
+import org.apache.pekko.actor.testkit.typed.annotations.JUnit5TestKit;
+import org.apache.pekko.actor.testkit.typed.javadsl.ActorTestKit;
+import org.apache.pekko.actor.testkit.typed.javadsl.LogCapturingExtension;
 import org.apache.pekko.actor.testkit.typed.javadsl.ManualTime;
-import org.apache.pekko.actor.testkit.typed.javadsl.TestKitJunitResource;
+import org.apache.pekko.actor.testkit.typed.javadsl.TestKitJUnit5Extension;
 import org.apache.pekko.actor.testkit.typed.javadsl.TestProbe;
 import org.apache.pekko.actor.typed.Behavior;
 import org.apache.pekko.actor.typed.javadsl.Behaviors;
-import org.junit.ClassRule;
-import org.junit.Rule;
-import org.junit.Test;
-import org.scalatestplus.junit.JUnitSuite;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
 
-public class ManualTimerExampleTest extends JUnitSuite {
+@ExtendWith({TestKitJUnit5Extension.class, LogCapturingExtension.class})
+public class ManualTimerExampleTest {
 
-  @ClassRule
-  public static final TestKitJunitResource testKit = new TestKitJunitResource(ManualTime.config());
-
-  @Rule public final LogCapturing logCapturing = new LogCapturing();
+  @JUnit5TestKit public ActorTestKit testKit = ActorTestKit.create(ManualTime.config());
 
   private final ManualTime manualTime = ManualTime.get(testKit.system());
 

actor-testkit-typed/src/test/java/jdocs/org/apache/pekko/actor/testkit/typed/javadsl/SyncTestingExampleTest.java

@@ -14,8 +14,8 @@
 package jdocs.org.apache.pekko.actor.testkit.typed.javadsl;
 
 // #imports
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.typesafe.config.Config;
 import java.time.Duration;
@@ -28,13 +28,12 @@
 import org.apache.pekko.actor.testkit.typed.javadsl.TestInbox;
 import org.apache.pekko.actor.typed.*;
 import org.apache.pekko.actor.typed.javadsl.*;
-import org.junit.Test;
-import org.scalatestplus.junit.JUnitSuite;
+import org.junit.jupiter.api.Test;
 import org.slf4j.event.Level;
 
 // #imports
 
-public class SyncTestingExampleTest extends JUnitSuite {
+public class SyncTestingExampleTest {
 
   // #child
   public static class Child {
@@ -315,20 +314,20 @@ public void testSupportContextualAsk() {
 
     // Completing/timing-out the ask is processed synchronously
     List<CapturedLogEvent> allLogEntries = test.getAllLogEntries();
-    assertEquals(allLogEntries.size(), 1);
+    assertEquals(1, allLogEntries.size());
 
     // The message, including the synthesized "replyTo", can be inspected from the effect
     assertEquals(question, effect.askMessage());
 
     // The response adaptation can be tested as many times as you want without completing the ask
     Hello.Command response1 = effect.adaptResponse(new Hello.Answer("No.  Who are you?"));
-    assertEquals(((Hello.GotAnAnswer) response1).answer, "No.  Who are you?");
+    assertEquals("No.  Who are you?", ((Hello.GotAnAnswer) response1).answer);
 
     // ... as can the message sent on a timeout
     assertTrue(effect.adaptTimeout() instanceof Hello.NoAnswerFrom);
 
     // The response timeout is captured
-    assertEquals(effect.responseTimeout().toSeconds(), 10L);
+    assertEquals(10L, effect.responseTimeout().toSeconds());
     // #test-contextual-ask
   }
 

actor-testkit-typed/src/test/java/org/apache/pekko/actor/testkit/typed/javadsl/ActorTestKitJUnit5Test.java

@@ -22,12 +22,11 @@
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
-import org.scalatestplus.junit.JUnitSuite;
 
 @DisplayName("ActorTestKitTestJUnit5")
 @ExtendWith(TestKitJUnit5Extension.class)
 @ExtendWith(LogCapturingExtension.class)
-class ActorTestKitJUnit5Test extends JUnitSuite {
+class ActorTestKitJUnit5Test {
 
   @JUnit5TestKit public ActorTestKit testKit = new JUnit5TestKitBuilder().build();
 

actor-testkit-typed/src/test/java/org/apache/pekko/actor/testkit/typed/javadsl/ActorTestKitTest.java

@@ -14,23 +14,21 @@
 package org.apache.pekko.actor.testkit.typed.javadsl;
 
 import static org.apache.pekko.Done.done;
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.HashMap;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
 import org.apache.pekko.Done;
+import org.apache.pekko.actor.testkit.typed.annotations.JUnit5TestKit;
 import org.apache.pekko.actor.typed.javadsl.Behaviors;
-import org.junit.ClassRule;
-import org.junit.Rule;
-import org.junit.Test;
-import org.scalatestplus.junit.JUnitSuite;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
 
-public class ActorTestKitTest extends JUnitSuite {
+@ExtendWith({TestKitJUnit5Extension.class, LogCapturingExtension.class})
+public class ActorTestKitTest {
 
-  @ClassRule public static TestKitJunitResource testKit = new TestKitJunitResource();
-
-  @Rule public final LogCapturing logCapturing = new LogCapturing();
+  @JUnit5TestKit public ActorTestKit testKit = new JUnit5TestKitBuilder().build();
 
   @Test
   public void systemNameShouldComeFromTestClassViaJunitResource() {

actor-testkit-typed/src/test/java/org/apache/pekko/actor/testkit/typed/javadsl/BehaviorTestKitTest.java

@@ -13,7 +13,7 @@
 
 package org.apache.pekko.actor.testkit.typed.javadsl;
 
-import static org.junit.Assert.*;
+import static org.junit.jupiter.api.Assertions.*;
 
 import java.time.Duration;
 import java.util.Arrays;
@@ -27,12 +27,11 @@
 import org.apache.pekko.actor.typed.Behavior;
 import org.apache.pekko.actor.typed.Props;
 import org.apache.pekko.actor.typed.javadsl.Behaviors;
-import org.junit.Ignore;
-import org.junit.Test;
-import org.scalatestplus.junit.JUnitSuite;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
 import org.slf4j.event.Level;
 
-public class BehaviorTestKitTest extends JUnitSuite {
+public class BehaviorTestKitTest {
 
   public interface Command {}
 
@@ -279,7 +278,7 @@ public void allowAssertionsOnEffectType() {
     BehaviorTestKit<Command> test = BehaviorTestKit.create(behavior);
     test.run(new SpawnChildren(1));
     Effect.Spawned spawned = test.expectEffectClass(Effect.Spawned.class);
-    assertEquals(spawned.childName(), "child0");
+    assertEquals("child0", spawned.childName());
   }
 
   @Test
@@ -323,7 +322,7 @@ public void returnEffectsThatHaveTakenPlace() {
   }
 
   @Test
-  @Ignore("Not supported for Java API")
+  @Disabled("Not supported for Java API")
   public void allowAssertionsUsingPartialFunctions() {}
 
   @Test

actor-testkit-typed/src/test/java/org/apache/pekko/actor/testkit/typed/javadsl/LoggingTestKitTest.java

@@ -13,24 +13,22 @@
 
 package org.apache.pekko.actor.testkit.typed.javadsl;
 
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.Collections;
 import java.util.Optional;
 import org.apache.pekko.actor.testkit.typed.LoggingEvent;
 import org.apache.pekko.actor.testkit.typed.TestException;
-import org.junit.ClassRule;
-import org.junit.Rule;
-import org.junit.Test;
-import org.scalatestplus.junit.JUnitSuite;
+import org.apache.pekko.actor.testkit.typed.annotations.JUnit5TestKit;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
 import org.slf4j.event.Level;
 
-public class LoggingTestKitTest extends JUnitSuite {
+@ExtendWith({TestKitJUnit5Extension.class, LogCapturingExtension.class})
+public class LoggingTestKitTest {
 
-  @ClassRule public static TestKitJunitResource testKit = new TestKitJunitResource();
-
-  @Rule public final LogCapturing logCapturing = new LogCapturing();
+  @JUnit5TestKit public ActorTestKit testKit = new JUnit5TestKitBuilder().build();
 
   private LoggingEvent errorNoCause() {
     return LoggingEvent.create(

actor-testkit-typed/src/test/java/org/apache/pekko/actor/testkit/typed/javadsl/TestProbeTest.java

@@ -13,23 +13,21 @@
 
 package org.apache.pekko.actor.testkit.typed.javadsl;
 
-import static org.junit.Assert.*;
+import static org.junit.jupiter.api.Assertions.*;
 
 import java.time.Duration;
 import java.util.Arrays;
 import java.util.List;
+import org.apache.pekko.actor.testkit.typed.annotations.JUnit5TestKit;
 import org.apache.pekko.actor.testkit.typed.scaladsl.TestProbeSpec;
 import org.apache.pekko.actor.testkit.typed.scaladsl.TestProbeSpec.*;
-import org.junit.ClassRule;
-import org.junit.Rule;
-import org.junit.Test;
-import org.scalatestplus.junit.JUnitSuite;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
 
-public class TestProbeTest extends JUnitSuite {
+@ExtendWith({TestKitJUnit5Extension.class, LogCapturingExtension.class})
+public class TestProbeTest {
 
-  @ClassRule public static TestKitJunitResource testKit = new TestKitJunitResource();
-
-  @Rule public final LogCapturing logCapturing = new LogCapturing();
+  @JUnit5TestKit public ActorTestKit testKit = new JUnit5TestKitBuilder().build();
 
   @Test
   public void testReceiveMessage() {
@@ -61,10 +59,14 @@ public void testReceiveMessageMaxDuration() {
     probe.expectNoMessage();
   }
 
-  @Test(expected = AssertionError.class)
+  @Test
   public void testReceiveMessageFailOnTimeout() {
-    TestProbe<EventT> probe = TestProbe.create(testKit.system());
-    probe.receiveMessage(Duration.ofMillis(100));
+    org.junit.jupiter.api.Assertions.assertThrows(
+        AssertionError.class,
+        () -> {
+          TestProbe<EventT> probe = TestProbe.create(testKit.system());
+          probe.receiveMessage(Duration.ofMillis(100));
+        });
   }
 
   @Test
@@ -92,12 +94,16 @@ public void testAwaitAssert() {
     assertEquals("some result", awaitAssertResult);
   }
 
-  @Test(expected = Exception.class)
+  @Test
   public void testAwaitAssertThrowingCheckedException() {
-    TestProbe<String> probe = TestProbe.create(testKit.system());
-    probe.awaitAssert(
+    org.junit.jupiter.api.Assertions.assertThrows(
+        Exception.class,
         () -> {
-          throw new Exception("checked exception");
+          TestProbe<String> probe = TestProbe.create(testKit.system());
+          probe.awaitAssert(
+              () -> {
+                throw new Exception("checked exception");
+              });
         });
   }