Add backward test cases.

Author: druidliu

tests/integration/src/test/java/org/apache/pulsar/tests/integration/backwardscompatibility/ClientOffloadTest3_0.java

@@ -0,0 +1,36 @@
+package org.apache.pulsar.tests.integration.backwardscompatibility;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Supplier;
+import org.apache.pulsar.tests.integration.containers.BrokerContainer;
+import org.apache.pulsar.tests.integration.containers.PulsarContainer;
+import org.apache.pulsar.tests.integration.offload.TestBaseOffload;
+import org.testng.annotations.Test;
+
+public class ClientOffloadTest3_0 extends TestBaseOffload {
+    @Override
+    protected Map<String, String> getEnv() {
+        Map<String, String> result = new HashMap<>();
+        result.put("managedLedgerMaxEntriesPerLedger", String.valueOf(getNumEntriesPerLedger()));
+        result.put("managedLedgerMinLedgerRolloverTimeMinutes", "0");
+        result.put("managedLedgerOffloadDriver", "filesystem");
+        result.put("fileSystemURI", "file:///tmp");
+
+        return result;
+    }
+
+    @Override
+    protected void beforeStartCluster() throws Exception {
+        super.beforeStartCluster();
+        for (BrokerContainer brokerContainer : pulsarCluster.getBrokers()) {
+            brokerContainer.setDockerImageName(PulsarContainer.PULSAR_3_0_IMAGE_NAME);
+        }
+    }
+
+    @Test(dataProvider = "ServiceAndAdminUrls")
+    public void testPublishOffloadAndConsumeDeletionLag(Supplier<String> serviceUrl, Supplier<String> adminUrl)
+            throws Exception {
+        super.testPublishOffloadAndConsumeDeletionLag(serviceUrl.get(), adminUrl.get());
+    }
+}

tests/integration/src/test/java/org/apache/pulsar/tests/integration/containers/PulsarContainer.java

@@ -54,6 +54,7 @@ public abstract class PulsarContainer<SelfT extends PulsarContainer<SelfT>> exte
     public static final String DEFAULT_IMAGE_NAME = System.getenv().getOrDefault("PULSAR_TEST_IMAGE_NAME",
             "apachepulsar/pulsar-test-latest-version:latest");
     public static final String DEFAULT_HTTP_PATH = "/metrics";
+    public static final String PULSAR_3_0_IMAGE_NAME = "apachepulsar/pulsar:3.0.0";
     public static final String PULSAR_2_5_IMAGE_NAME = "apachepulsar/pulsar:2.5.0";
     public static final String PULSAR_2_4_IMAGE_NAME = "apachepulsar/pulsar:2.4.0";
     public static final String PULSAR_2_3_IMAGE_NAME = "apachepulsar/pulsar:2.3.0";