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import {
afterEach,
beforeEach,
describe,
expect,
it,
jest,
} from '@jest/globals';
import { act, renderHook } from '@testing-library/react';
import type { ReactNode } from 'react';
import { SWRConfig } from 'swr';
import { fetchPostsList } from '../../../services/graphql';
import { usePostsList } from './use-posts-list';
const wrapper = ({ children }: { children?: ReactNode }) => {
const map = new Map();
return (
<SWRConfig
value={{
provider: () => map,
isOnline() {
return true;
},
isVisible() {
return true;
},
initFocus() {
/* nothing */
},
initReconnect() {
/* nothing */
},
}}
>
{children}
</SWRConfig>
);
};
describe('usePostsList', () => {
beforeEach(() => {
/* Not sure why it is needed, but without it Jest was complaining with `You
* are trying to import a file after the Jest environment has been torn
* down`... Maybe because of useSWR? */
jest.useFakeTimers({
doNotFake: ['queueMicrotask'],
});
});
afterEach(() => {
jest.runOnlyPendingTimers();
jest.useRealTimers();
});
it('can return the first new result index when loading more posts', async () => {
const perPage = 5;
const { result } = renderHook(
() => usePostsList({ fetcher: fetchPostsList, perPage }),
{ wrapper }
);
expect.assertions(2);
expect(result.current.firstNewResultIndex).toBeUndefined();
await act(async () => {
await result.current.loadMore();
});
// Assuming there is more than one page.
expect(result.current.firstNewResultIndex).toBe(perPage + 1);
});
});
|
