joplin/packages/app-desktop/gui/NoteListItem/utils/useRootElement.test.ts

import { act, renderHook } from '@testing-library/react-hooks';
import useRootElement from './useRootElement';

describe('useRootElement', () => {
	beforeEach(() => {
		jest.useFakeTimers({ advanceTimers: true });
	});

	test('should find an element with a matching ID', async () => {
		const testElement = document.createElement('div');
		testElement.id = 'test-element-id';
		document.body.appendChild(testElement);

		const { result } = renderHook(useRootElement, {
			initialProps: testElement.id,
		});
		await act(async () => {
			await jest.advanceTimersByTimeAsync(100);
		});
		expect(result.current).toBe(testElement);

		testElement.remove();
	});

	test('should redo the element search when the elementId prop changes', async () => {
		const testElement = document.createElement('div');
		document.body.appendChild(testElement);

		const { rerender, result } = renderHook(useRootElement, {
			initialProps: 'some-id-here',
		});
		await jest.advanceTimersByTimeAsync(100);
		expect(result.current).toBe(null);

		// Searching for another non-existent ID: Should not match
		rerender('updated-id');
		await jest.advanceTimersByTimeAsync(100);
		expect(result.current).toBe(null);

		// Should not match the first element if its ID is set to the original (search
		// should be cancelled).
		testElement.id = 'some-id-here';
		await jest.advanceTimersByTimeAsync(100);
		expect(result.current).toBe(null);

		// Should match if the element ID changes to the updated ID.
		await act(async () => {
			testElement.id = 'updated-id';
			await jest.advanceTimersByTimeAsync(100);
		});
		expect(result.current).toBe(testElement);

		testElement.remove();
	});
});