old_contents: const testingLibrary = require('@testing-library/dom');
  const Mocha = require('mocha');
  const createDOM = require('./createDOM');
  const { createMochaHooks } = require('./mochaHooks');
  
  // Enable missing act warnings: https://github.com/facebook/react/blob/v16.13.1/packages/react-reconciler/src/ReactFiberHooks.js#L965
  // TODO: Revisit once https://github.com/facebook/react/issues/15439 is resolved.
  global.jest = null;
  
  createDOM();
  require('./init');
  
  testingLibrary.configure({
    // JSDOM logs errors otherwise on `getComputedStyles(element, pseudoElement)` calls.
    computedStyleSupportsPseudoElements: false,
  });
  
  const mochaHooks = createMochaHooks(Mocha);
  
  module.exports = { mochaHooks };
  
new_contents: const testingLibrary = require('@testing-library/dom');
  const Mocha = require('mocha');
  const createDOM = require('./createDOM');
  const { createMochaHooks } = require('./mochaHooks');
  
  // Enable missing act warnings: https://github.com/reactwg/react-18/discussions/102
  global.jest = null;
  global.IS_REACT_ACT_ENVIRONMENT = true;
  
  createDOM();
  require('./init');
  
  testingLibrary.configure({
    // JSDOM logs errors otherwise on `getComputedStyles(element, pseudoElement)` calls.
    computedStyleSupportsPseudoElements: false,
  });
  
  const mochaHooks = createMochaHooks(Mocha);
  
  module.exports = { mochaHooks };
  
subject: Enable "missing act" warnings using new proposal (#29167)