[FLINK-38809][Tests] Migrate flink-end-to-end-tests-common from JUnit4 to JUnit5

Testcontainers 2.0.2 removed JUnit4 support, requiring migration to JUnit5. Created local ExternalResource interface to be fully JUnit5-compatible with minimum code changes.

This migration allows the module to work with Testcontainers 2.0.2 while maintaining all existing test functionality.

Author: MartijnVisser

flink-end-to-end-tests/flink-end-to-end-tests-common/src/main/java/org/apache/flink/tests/util/ExternalResource.java

@@ -0,0 +1,41 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.flink.tests.util;
+
+/**
+ * Resource lifecycle interface for end-to-end tests.
+ *
+ * <p>This interface provides hooks for resource setup and cleanup, allowing resources to
+ * differentiate between successful and failed tests in their cleanup methods.
+ *
+ * <p>This is a JUnit5-compatible version that does not extend TestRule.
+ */
+public interface ExternalResource {
+
+    /** Called before the test execution. */
+    void before() throws Exception;
+
+    /** Called after successful test execution. */
+    void afterTestSuccess();
+
+    /** Called after failed test execution. Defaults to calling {@link #afterTestSuccess()}. */
+    default void afterTestFailure() {
+        afterTestSuccess();
+    }
+}

flink-end-to-end-tests/flink-end-to-end-tests-common/src/main/java/org/apache/flink/tests/util/activation/OperatingSystemRestriction.java

@@ -20,8 +20,8 @@
 
 import org.apache.flink.util.OperatingSystem;
 
-import org.junit.Assume;
-import org.junit.AssumptionViolatedException;
+import org.junit.jupiter.api.Assumptions;
+import org.opentest4j.TestAbortedException;
 
 import java.util.Arrays;
 import java.util.EnumSet;
@@ -39,26 +39,27 @@ public enum OperatingSystemRestriction {
      *
      * @param reason reason for the restriction
      * @param operatingSystems allowed operating systems
-     * @throws AssumptionViolatedException if this method is called on a forbidden operating system
+     * @throws TestAbortedException if this method is called on a forbidden operating system
      */
     public static void restrictTo(final String reason, final OperatingSystem... operatingSystems)
-            throws AssumptionViolatedException {
+            throws TestAbortedException {
         final EnumSet<OperatingSystem> allowed = EnumSet.copyOf(Arrays.asList(operatingSystems));
-        Assume.assumeTrue(reason, allowed.contains(OperatingSystem.getCurrentOperatingSystem()));
+        Assumptions.assumeTrue(
+                allowed.contains(OperatingSystem.getCurrentOperatingSystem()), reason);
     }
 
     /**
      * Forbids the execution on the given set of operating systems.
      *
      * @param reason reason for the restriction
      * @param forbiddenSystems forbidden operating systems
-     * @throws AssumptionViolatedException if this method is called on a forbidden operating system
+     * @throws TestAbortedException if this method is called on a forbidden operating system
      */
     public static void forbid(final String reason, final OperatingSystem... forbiddenSystems)
-            throws AssumptionViolatedException {
+            throws TestAbortedException {
         final OperatingSystem os = OperatingSystem.getCurrentOperatingSystem();
         for (final OperatingSystem forbiddenSystem : forbiddenSystems) {
-            Assume.assumeTrue(reason, os != forbiddenSystem);
+            Assumptions.assumeTrue(os != forbiddenSystem, reason);
         }
     }
 }

flink-end-to-end-tests/flink-end-to-end-tests-common/src/main/java/org/apache/flink/tests/util/cache/DownloadCache.java

@@ -18,8 +18,8 @@
 
 package org.apache.flink.tests.util.cache;
 
+import org.apache.flink.tests.util.ExternalResource;
 import org.apache.flink.tests.util.util.FactoryUtils;
-import org.apache.flink.util.ExternalResource;
 
 import java.io.IOException;
 import java.nio.file.Path;

flink-end-to-end-tests/flink-end-to-end-tests-common/src/main/java/org/apache/flink/tests/util/cache/LolCache.java

@@ -18,8 +18,10 @@
 
 package org.apache.flink.tests.util.cache;
 
-import org.junit.rules.TemporaryFolder;
+import org.apache.flink.util.FileUtils;
 
+import java.io.IOException;
+import java.nio.file.Path;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -31,16 +33,20 @@
 public final class LolCache extends AbstractDownloadCache {
 
     private static final Pattern CACHE_FILE_NAME_PATTERN = Pattern.compile(".*");
-    private final TemporaryFolder folder;
+    private final Path tempDirectory;
 
-    public LolCache(TemporaryFolder folder) {
-        super(folder.getRoot().toPath());
-        this.folder = folder;
+    public LolCache(Path tempDirectory) {
+        super(tempDirectory);
+        this.tempDirectory = tempDirectory;
     }
 
     @Override
     public void afterTestSuccess() {
-        folder.delete();
+        try {
+            FileUtils.deleteDirectory(tempDirectory.toFile());
+        } catch (IOException e) {
+            // Ignore cleanup failures
+        }
     }
 
     @Override

flink-end-to-end-tests/flink-end-to-end-tests-common/src/main/java/org/apache/flink/tests/util/cache/LolCacheFactory.java

@@ -18,17 +18,16 @@
 
 package org.apache.flink.tests.util.cache;
 
-import org.junit.rules.TemporaryFolder;
-
 import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
 
 /** A {@link DownloadCacheFactory} for the {@link LolCache}. */
 public final class LolCacheFactory implements DownloadCacheFactory {
 
     @Override
     public DownloadCache create() throws IOException {
-        final TemporaryFolder folder = new TemporaryFolder();
-        folder.create();
-        return new LolCache(folder);
+        final Path tempDirectory = Files.createTempDirectory("flink-lol-cache-");
+        return new LolCache(tempDirectory);
     }
 }

flink-end-to-end-tests/flink-end-to-end-tests-common/src/main/java/org/apache/flink/tests/util/flink/FlinkResource.java

@@ -19,8 +19,8 @@
 package org.apache.flink.tests.util.flink;
 
 import org.apache.flink.test.util.JobSubmission;
+import org.apache.flink.tests.util.ExternalResource;
 import org.apache.flink.tests.util.util.FactoryUtils;
-import org.apache.flink.util.ExternalResource;
 
 import java.io.IOException;
 import java.time.Duration;

flink-end-to-end-tests/flink-end-to-end-tests-common/src/main/java/org/apache/flink/tests/util/flink/LocalStandaloneFlinkResource.java

@@ -29,17 +29,18 @@
 import org.apache.flink.test.util.SQLJobSubmission;
 import org.apache.flink.tests.util.TestUtils;
 import org.apache.flink.util.ConfigurationException;
+import org.apache.flink.util.FileUtils;
 import org.apache.flink.util.concurrent.Executors;
 import org.apache.flink.util.concurrent.FutureUtils;
 
-import org.junit.rules.TemporaryFolder;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.slf4j.event.Level;
 
 import javax.annotation.Nullable;
 
 import java.io.IOException;
+import java.nio.file.Files;
 import java.nio.file.Path;
 import java.time.Duration;
 import java.util.Collections;
@@ -58,12 +59,12 @@ public class LocalStandaloneFlinkResource implements FlinkResource {
 
     private static final Logger LOG = LoggerFactory.getLogger(LocalStandaloneFlinkResource.class);
 
-    private final TemporaryFolder temporaryFolder = new TemporaryFolder();
     private final Path distributionDirectory;
     @Nullable private final Path logBackupDirectory;
     private final FlinkResourceSetup setup;
 
     private FlinkDistribution distribution;
+    private Path tempDirectory;
 
     LocalStandaloneFlinkResource(
             Path distributionDirectory,
@@ -77,8 +78,8 @@ public class LocalStandaloneFlinkResource implements FlinkResource {
 
     @Override
     public void before() throws Exception {
-        temporaryFolder.create();
-        Path tmp = temporaryFolder.newFolder().toPath();
+        tempDirectory = Files.createTempDirectory("flink-local-standalone-");
+        Path tmp = Files.createDirectory(tempDirectory.resolve("dist"));
         LOG.info("Copying distribution to {}.", tmp);
         TestUtils.copyDirectory(distributionDirectory, tmp);
 
@@ -98,7 +99,7 @@ public void before() throws Exception {
     @Override
     public void afterTestSuccess() {
         shutdownCluster();
-        temporaryFolder.delete();
+        cleanupTempDirectory();
     }
 
     @Override
@@ -107,7 +108,17 @@ public void afterTestFailure() {
             shutdownCluster();
             backupLogs();
         }
-        temporaryFolder.delete();
+        cleanupTempDirectory();
+    }
+
+    private void cleanupTempDirectory() {
+        if (tempDirectory != null) {
+            try {
+                FileUtils.deleteDirectory(tempDirectory.toFile());
+            } catch (IOException e) {
+                LOG.warn("Failed to delete temporary directory: {}", tempDirectory, e);
+            }
+        }
     }
 
     private void shutdownCluster() {

flink-end-to-end-tests/flink-end-to-end-tests-common/src/test/java/org/apache/flink/tests/util/TestUtilsTest.java

@@ -21,23 +21,23 @@
 import org.apache.flink.util.OperatingSystem;
 import org.apache.flink.util.TestLogger;
 
-import org.junit.Assert;
-import org.junit.BeforeClass;
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.rules.TemporaryFolder;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
 /** Tests for {@link TestUtils}. */
 public class TestUtilsTest extends TestLogger {
 
-    @Rule public final TemporaryFolder temporaryFolder = new TemporaryFolder();
+    @TempDir Path temporaryFolder;
 
-    @BeforeClass
+    @BeforeAll
     public static void setupClass() {
         OperatingSystemRestriction.forbid(
                 "Symbolic links usually require special permissions on Windows.",
@@ -50,7 +50,7 @@ public void copyDirectory() throws IOException {
             Paths.get("file1"), Paths.get("dir1", "file2"),
         };
 
-        Path source = temporaryFolder.newFolder("source").toPath();
+        Path source = Files.createDirectory(temporaryFolder.resolve("source"));
         for (Path file : files) {
             Files.createDirectories(source.resolve(file).getParent());
             Files.createFile(source.resolve(file));
@@ -63,7 +63,7 @@ public void copyDirectory() throws IOException {
         TestUtils.copyDirectory(symbolicLink, target);
 
         for (Path file : files) {
-            Assert.assertTrue(Files.exists(target.resolve(file)));
+            assertTrue(Files.exists(target.resolve(file)));
         }
     }
 }

flink-end-to-end-tests/flink-end-to-end-tests-common/src/test/java/org/apache/flink/tests/util/util/FileUtilsTest.java

@@ -20,11 +20,9 @@
 import org.apache.flink.test.util.FileUtils;
 import org.apache.flink.util.TestLogger;
 
-import org.junit.Assert;
-import org.junit.Before;
-import org.junit.ClassRule;
-import org.junit.Test;
-import org.junit.rules.TemporaryFolder;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 
 import java.io.IOException;
 import java.nio.file.Files;
@@ -34,18 +32,20 @@
 import java.util.List;
 import java.util.regex.Pattern;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 /** Tests for {@link FileUtils}. */
 public class FileUtilsTest extends TestLogger {
 
-    @ClassRule public static final TemporaryFolder TMP = new TemporaryFolder();
+    @TempDir static Path tempDir;
 
     private static final List<String> ORIGINAL_LINES =
             Collections.unmodifiableList(Arrays.asList("line1", "line2", "line3"));
     private Path testFile;
 
-    @Before
+    @BeforeEach
     public void setupFile() throws IOException {
-        Path path = TMP.newFile().toPath();
+        Path path = Files.createTempFile(tempDir, null, null);
 
         Files.write(path, ORIGINAL_LINES);
 
@@ -56,7 +56,7 @@ public void setupFile() throws IOException {
     public void replaceSingleMatch() throws IOException {
         FileUtils.replace(testFile, Pattern.compile("line1"), matcher -> "removed");
 
-        Assert.assertEquals(
+        assertEquals(
                 Arrays.asList("removed", ORIGINAL_LINES.get(1), ORIGINAL_LINES.get(2)),
                 Files.readAllLines(testFile));
     }
@@ -65,14 +65,14 @@ public void replaceSingleMatch() throws IOException {
     public void replaceMultipleMatch() throws IOException {
         FileUtils.replace(testFile, Pattern.compile("line(.*)"), matcher -> matcher.group(1));
 
-        Assert.assertEquals(Arrays.asList("1", "2", "3"), Files.readAllLines(testFile));
+        assertEquals(Arrays.asList("1", "2", "3"), Files.readAllLines(testFile));
     }
 
     @Test
     public void replaceWithEmptyLine() throws IOException {
         FileUtils.replace(testFile, Pattern.compile("line2"), matcher -> "");
 
-        Assert.assertEquals(
+        assertEquals(
                 Arrays.asList(ORIGINAL_LINES.get(0), "", ORIGINAL_LINES.get(2)),
                 Files.readAllLines(testFile));
     }