From fb15048314de2cca16b58d4c18f9519c0a4ec12c Mon Sep 17 00:00:00 2001
From: yash-rajpal <rajpal.yash03@gmail.com>
Date: Tue, 7 Jan 2025 21:31:35 +0530
Subject: [PATCH] add unit test

---
 .../views/room/body/hooks/useGetMore.spec.ts  | 84 +++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100644 apps/meteor/client/views/room/body/hooks/useGetMore.spec.ts

diff --git a/apps/meteor/client/views/room/body/hooks/useGetMore.spec.ts b/apps/meteor/client/views/room/body/hooks/useGetMore.spec.ts
new file mode 100644
index 000000000000..93c2ab23ae15
--- /dev/null
+++ b/apps/meteor/client/views/room/body/hooks/useGetMore.spec.ts
@@ -0,0 +1,84 @@
+import { renderHook } from '@testing-library/react';
+import React from 'react';
+
+import { useGetMore } from './useGetMore';
+import { RoomHistoryManager } from '../../../../../app/ui-utils/client';
+
+jest.mock('../../../../../app/ui-utils/client', () => ({
+	RoomHistoryManager: {
+		isLoading: jest.fn(),
+		hasMore: jest.fn(),
+		hasMoreNext: jest.fn(),
+		getMore: jest.fn(),
+		getMoreNext: jest.fn(),
+	},
+}));
+
+jest.mock('../../../../../lib/utils/highOrderFunctions', () => ({
+	withThrottling: jest.fn().mockImplementation(() => (fn: () => void) => fn),
+}));
+
+const mockGetMore = jest.fn();
+
+describe('useGetMore', () => {
+	it('should call getMore when scrolling near top and hasMore is true', () => {
+		(RoomHistoryManager.isLoading as jest.Mock).mockReturnValue(false);
+		(RoomHistoryManager.hasMore as jest.Mock).mockReturnValue(true);
+		(RoomHistoryManager.hasMoreNext as jest.Mock).mockReturnValue(false);
+		(RoomHistoryManager.getMore as jest.Mock).mockImplementation(mockGetMore);
+		const atBottomRef = { current: false };
+
+		const mockElement = {
+			addEventListener: jest.fn((event, handler) => {
+				if (event === 'scroll') {
+					handler({
+						target: {
+							scrollTop: 10,
+							clientHeight: 300,
+						},
+					});
+				}
+			}),
+			removeEventListener: jest.fn(),
+		};
+
+		const useRefSpy = jest.spyOn(React, 'useRef').mockReturnValueOnce({ current: mockElement });
+
+		const { unmount } = renderHook(() => useGetMore('room-id', atBottomRef), { legacyRoot: true });
+
+		expect(useRefSpy).toHaveBeenCalledWith(null);
+		expect(RoomHistoryManager.getMore).toHaveBeenCalledWith('room-id');
+
+		unmount();
+		expect(mockElement.removeEventListener).toHaveBeenCalledWith('scroll', expect.any(Function));
+	});
+
+	it('should call getMoreNext when scrolling near bottom and hasMoreNext is true', () => {
+		(RoomHistoryManager.isLoading as jest.Mock).mockReturnValue(false);
+		(RoomHistoryManager.hasMore as jest.Mock).mockReturnValue(false);
+		(RoomHistoryManager.hasMoreNext as jest.Mock).mockReturnValue(true);
+		(RoomHistoryManager.getMoreNext as jest.Mock).mockImplementation(mockGetMore);
+
+		const atBottomRef = { current: false };
+		const mockElement = {
+			addEventListener: jest.fn((event, handler) => {
+				if (event === 'scroll') {
+					handler({
+						target: {
+							scrollTop: 600,
+							clientHeight: 300,
+							scrollHeight: 800,
+						},
+					});
+				}
+			}),
+			removeEventListener: jest.fn(),
+		};
+		const useRefSpy = jest.spyOn(React, 'useRef').mockReturnValueOnce({ current: mockElement });
+
+		renderHook(() => useGetMore('room-id', atBottomRef), { legacyRoot: true });
+
+		expect(useRefSpy).toHaveBeenCalledWith(null);
+		expect(RoomHistoryManager.getMoreNext).toHaveBeenCalledWith('room-id', atBottomRef);
+	});
+});