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import { act, renderHook } from '@testing-library/react-hooks';
import useGetSet from '../src/useGetSet';
const setUp = (initialValue: any) => renderHook(() => useGetSet(initialValue));
beforeEach(() => {
jest.useFakeTimers();
});
it('should init getter and setter', () => {
const { result } = setUp('foo');
const [get, set] = result.current;
expect(get).toBeInstanceOf(Function);
expect(set).toBeInstanceOf(Function);
});
it('should get current value', () => {
const { result } = setUp('foo');
const [get] = result.current;
const currentValue = get();
expect(currentValue).toBe('foo');
});
it('should set new value', () => {
const { result } = setUp('foo');
const [get, set] = result.current;
act(() => set('bar'));
const currentValue = get();
expect(currentValue).toBe('bar');
});
/**
* This test implements the special demo in storybook that increments a number
* after 1 second on each click.
*/
it('should get and set expected values when used in nested functions', () => {
const onClick = jest.fn(() => {
setTimeout(() => {
set(get() + 1);
}, 1000);
});
const { result } = setUp(0);
const [get, set] = result.current;
// simulate 3 clicks
onClick();
onClick();
onClick();
// fast-forward until all timers have been executed
act(() => {
jest.runAllTimers();
});
const currentValue = get();
expect(currentValue).toBe(3);
expect(onClick).toHaveBeenCalledTimes(3);
});
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