Add an integration test that covers critical history pagination code

temporal-sdk/src/test/java/io/temporal/workflow/LongWorkflowHistoryServerPaginationTest.java

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+/*
+ * Copyright (C) 2022 Temporal Technologies, Inc. All Rights Reserved.
+ *
+ * Copyright (C) 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Modifications copyright (C) 2017 Uber Technologies, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this material 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 io.temporal.workflow;
+
+import static org.junit.Assert.assertEquals;
+
+import io.temporal.activity.ActivityOptions;
+import io.temporal.client.WorkflowStub;
+import io.temporal.common.RetryOptions;
+import io.temporal.internal.Signal;
+import io.temporal.testing.internal.SDKTestOptions;
+import io.temporal.testing.internal.SDKTestWorkflowRule;
+import io.temporal.workflow.shared.TestActivities;
+import io.temporal.workflow.shared.TestWorkflows;
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.Rule;
+import org.junit.Test;
+
+/**
+ * Covers ServiceWorkflowHistoryIterator with an integration test that includes a server pagination
+ */
+public class LongWorkflowHistoryServerPaginationTest {
+  private static final Signal ACTIVITIES_COMPLETED = new Signal();
+
+  @Rule
+  public SDKTestWorkflowRule testWorkflowRule =
+      SDKTestWorkflowRule.newBuilder()
+          .setWorkflowTypes(TestLongHistoryWorkflow.class)
+          .setActivityImplementations(new TestActivities.TestActivitiesImpl())
+          .setUseTimeskipping(false)
+          .build();
+
+  @Test(timeout = 20_000)
+  public void longWorkflowTriggeringServerPaginationCanFinish() throws InterruptedException {
+    RetryOptions workflowRetryOptions =
+        RetryOptions.newBuilder()
+            .setInitialInterval(Duration.ofMillis(1))
+            .setMaximumAttempts(2)
+            .setBackoffCoefficient(1.0)
+            .build();
+    TestWorkflows.TestWorkflowReturnString typedStub =
+        testWorkflowRule
+            .getWorkflowClient()
+            .newWorkflowStub(
+                TestWorkflows.TestWorkflowReturnString.class,
+                SDKTestOptions.newWorkflowOptionsWithTimeouts(testWorkflowRule.getTaskQueue())
+                    .toBuilder()
+                    .setRetryOptions(workflowRetryOptions)
+                    .build());
+
+    WorkflowStub untypedStub = WorkflowStub.fromTyped(typedStub);
+    untypedStub.start();
+
+    ACTIVITIES_COMPLETED.waitForSignal();
+    testWorkflowRule.invalidateWorkflowCache();
+
+    assertEquals("success", untypedStub.getResult(String.class));
+  }
+
+  public static class TestLongHistoryWorkflow implements TestWorkflows.TestWorkflowReturnString {
+
+    private final TestActivities.VariousTestActivities activities =
+        Workflow.newActivityStub(
+            TestActivities.VariousTestActivities.class,
+            ActivityOptions.newBuilder()
+                .setScheduleToCloseTimeout(Duration.ofSeconds(200))
+                .build());
+
+    @Override
+    public String execute() {
+      List<Promise<String>> promises = new ArrayList<>();
+
+      // Pagination is triggered after 256 batches of event and each batch may contain >1 events.
+      // All events created by WFT completion commands are in the same batch with workflow task
+      // completion.
+      // We want to paginate at least through two pages
+      for (int j = 0; j < 512; j++) {
+        Promise<String> function = Async.function(activities::activity);
+        promises.add(function);
+      }
+      Promise.allOf(promises).get();
+
+      ACTIVITIES_COMPLETED.signal();
+      // test code calls invalidate here and the next workflow task will cause replay with
+      // pagination
+
+      Workflow.sleep(Duration.ofSeconds(3));
+
+      return "success";
+    }
+  }
+}