MINOR: Rewrite RaftClusterSnapshotTest from Scala to Java

Author: JiayaoS

core/src/test/java/kafka/server/RaftClusterSnapshotTest.java

@@ -0,0 +1,104 @@
+/*
+ * 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 kafka.server;
+
+import kafka.raft.KafkaRaftManager;
+
+import org.apache.kafka.common.test.KafkaClusterTestKit;
+import org.apache.kafka.common.test.TestKitNodes;
+import org.apache.kafka.common.utils.LogContext;
+import org.apache.kafka.common.utils.internals.BufferSupplier;
+import org.apache.kafka.metadata.MetadataRecordSerde;
+import org.apache.kafka.raft.MetadataLogConfig;
+import org.apache.kafka.server.common.ApiMessageAndVersion;
+import org.apache.kafka.snapshot.RecordsSnapshotReader;
+import org.apache.kafka.test.TestUtils;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
+
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+@Timeout(120)
+public class RaftClusterSnapshotTest {
+
+    @Test
+    public void testSnapshotsGenerated() throws Exception {
+        int numberOfBrokers = 3;
+        int numberOfControllers = 3;
+
+        try (var cluster = new KafkaClusterTestKit.Builder(
+                new TestKitNodes.Builder()
+                        .setNumBrokerNodes(numberOfBrokers)
+                        .setNumControllerNodes(numberOfControllers)
+                        .build())
+                .setConfigProp(MetadataLogConfig.METADATA_SNAPSHOT_MAX_NEW_RECORD_BYTES_CONFIG, "10")
+                .setConfigProp(MetadataLogConfig.METADATA_MAX_IDLE_INTERVAL_MS_CONFIG, "0")
+                .build()) {
+
+            cluster.format();
+            cluster.startup();
+
+            // Check that every controller and broker has a snapshot
+            TestUtils.waitForCondition(
+                    () -> cluster.raftManagers().values().stream()
+                            .allMatch(raftManager -> raftManager.raftLog().latestSnapshotId().isPresent()),
+                    () -> "Expected for every controller and broker to generate a snapshot: " +
+                            cluster.raftManagers().entrySet().stream()
+                                    .collect(Collectors.toMap(
+                                            Map.Entry::getKey,
+                                            e -> e.getValue().raftLog().latestSnapshotId()
+                                    ))
+            );
+
+            assertEquals(numberOfControllers + numberOfBrokers, cluster.raftManagers().size());
+
+            // For every controller and broker perform some sanity checks against the latest snapshot
+            for (KafkaRaftManager<ApiMessageAndVersion> raftManager : cluster.raftManagers().values()) {
+                try (var snapshot = RecordsSnapshotReader.of(
+                        raftManager.raftLog().latestSnapshot().get(),
+                        new MetadataRecordSerde(),
+                        BufferSupplier.create(),
+                        1,
+                        true,
+                        new LogContext()
+                )) {
+                    // Check that the snapshot is non-empty
+                    assertTrue(snapshot.hasNext());
+
+                    // Check that we can read the entire snapshot
+                    while (snapshot.hasNext()) {
+                        var batch = snapshot.next();
+                        assertTrue(batch.sizeInBytes() > 0);
+                        // A batch must have at least one control records or at least one data records, but not both
+                        assertNotEquals(
+                                batch.records().isEmpty(),
+                                batch.controlRecords().isEmpty(),
+                                "data records = " + batch.records() + "; control records = " + batch.controlRecords()
+                        );
+                    }
+                }
+            }
+        }
+    }
+}