[8.17] [Security Solution] Fix timeline dynamic batching (#204034)

x-pack/plugins/security_solution/common/types/timeline/store.ts

@@ -72,8 +72,8 @@ export type OnColumnRemoved = (columnId: ColumnId) => void;
 
 export type OnColumnResized = ({ columnId, delta }: { columnId: ColumnId; delta: number }) => void;
 
-/** Invoked when a user clicks to load more item */
-export type OnFetchMoreRecords = (nextPage: number) => void;
+/** Invoked when a user clicks to load next batch */
+export type OnFetchMoreRecords = VoidFunction;
 
 /** Invoked when a user checks/un-checks a row */
 export type OnRowSelected = ({

x-pack/plugins/security_solution/public/common/mock/mock_timeline_search_service.ts

@@ -0,0 +1,51 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import { mockTimelineData } from './mock_timeline_data';
+
+const mockEvents = structuredClone(mockTimelineData);
+
+/*
+ * This helps to mock `data.search.search` method to mock the timeline data
+ * */
+export const getMockTimelineSearchSubscription = () => {
+  const mockSearchWithArgs = jest.fn();
+
+  const mockTimelineSearchSubscription = jest.fn().mockImplementation((args) => {
+    mockSearchWithArgs(args);
+    return {
+      subscribe: jest.fn().mockImplementation(({ next }) => {
+        const start = args.pagination.activePage * args.pagination.querySize;
+        const end = start + args.pagination.querySize;
+        const timelineOut = setTimeout(() => {
+          next({
+            isRunning: false,
+            isPartial: false,
+            inspect: {
+              dsl: [],
+              response: [],
+            },
+            edges: mockEvents.map((item) => ({ node: item })).slice(start, end),
+            pageInfo: {
+              activePage: args.pagination.activePage,
+              querySize: args.pagination.querySize,
+            },
+            rawResponse: {},
+            totalCount: mockEvents.length,
+          });
+        }, 50);
+        return {
+          unsubscribe: jest.fn(() => {
+            clearTimeout(timelineOut);
+          }),
+        };
+      }),
+    };
+  });
+
+  return { mockTimelineSearchSubscription, mockSearchWithArgs };
+};