let React;

let ReactNoop;

let Scheduler;

let act;

let assertLog;

describe('ReactClassSetStateCallback', () => {

  beforeEach(() => {

    jest.resetModules();

    React = require('react');

    ReactNoop = require('react-noop-renderer');

    Scheduler = require('scheduler');

    act = require('internal-test-utils').act;

    const InternalTestUtils = require('internal-test-utils');

    assertLog = InternalTestUtils.assertLog;

  });

  function Text({text}) {

    Scheduler.log(text);

    return text;

  }

  test('regression: setState callback (2nd arg) should only fire once, even after a rebase', async () => {

    let app;

    class App extends React.Component {

      state = {step: 0};

      render() {

        app = this;

        return <Text text={this.state.step} />;

      }

    }

    const root = ReactNoop.createRoot();

    await act(() => {

      root.render(<App />);

    });

    assertLog([0]);

    await act(() => {

      if (gate(flags => flags.enableUnifiedSyncLane)) {

        React.startTransition(() => {

          app.setState({step: 1}, () => Scheduler.log('Callback 1'));

        });

      } else {

        app.setState({step: 1}, () => Scheduler.log('Callback 1'));

      }

      ReactNoop.flushSync(() => {

        app.setState({step: 2}, () => Scheduler.log('Callback 2'));

      });

    });

    assertLog([2, 'Callback 2', 2, 'Callback 1']);

  });

});