Using Jest mock timers and waitFor together causes tests to timeout

[dcalhoun]

Describe the bug

Related to #391. Using jest.useFakeTimers() in combination with waitFor, causes the tests using waitFor to fail due to timeout error:

Timeout - Async callback was not invoked within the 5000 ms timeout specified by jest.setTimeout.Error: Timeout - Async callback was not invoked within the 5000 ms timeout specified by jest.setTimeout.

Relying upon jest.useFakeTimers("modern") instead causes the above failure for all tests if the file merely imports waitFor at all, regardless if the given test uses waitFor or not.

Expected behavior

All tests in the reproduction test case should pass.

Steps to Reproduce

1. Clone the reproduction test case.
2. yarn install
3. yarn test

Versions

npmPackages:
    @testing-library/react-native: ^7.0.1 => 7.0.1 
    react: ^16.13.1 => 16.13.1 
    react-native: ^0.63.2 => 0.63.2 
    react-test-renderer: ^16.13.1 => 16.13.1

[mdjastrzebski]

Not sure if I understood your issues correctly. AFAIK when using fake timers you should not use call waitFor with await.

Please compare how were are using fake timers with waitFor in our own test suit.

It seems that just this change (await waitFor(() => { -> waitFor(() => {) fixes your legacy-timers.test.js.

Not sure how to fix your failing tests using modern timers.

[dcalhoun]

@mdjastrzebski thank you for the response. What you said about not awaiting the return of waitFor when using fake timers makes sense. I now understand the following statement from the waitFor documentation.

If you're using Jest's Timer Mocks, remember not to use async/await syntax as it will stall your tests.

The phrasing of that always confused me, but I now understand. I'll likely open a PR to improve that piece of documentation.

That said, it is still confusing as to why modern timers causes all of the tests to fail in my test case. I'd appreciate any guidance you are able to provide on that issue. Thanks!

[mdjastrzebski]

@thymikee maybe you can with modern times here.

[thymikee]

Running jest.runOnlyPendingTimers() or jest.runAllTimers() doesn't help? waitFor relies on setTimeout internally, so that may be a thing

[dcalhoun]

@thymikee no, running jest.runOnlyPendingTimers() or jest.runAllTimers() does not appear to fix the issue. I could understand if waitFor and timer mocks were fundamentally incompatible, but I wanted to seek out if that is the case. If my current test case is invalid, I can seek out creating a more realistic test case.

That said, it is curious that "legacy" timers can work, but "modern" timers do not. It is particularly odd that enabling "modern" timers will break a test file if you merely import waitFor. One does not even need to invoke waitFor for tests in the given file to fail. Do you know why that would be the case?

Is it possible to use "modern" timers and waitFor together?

[thymikee]

Not really sure where the incompatibility comes from. We already had fixed some issues around this topic here: #397, please take a look. In our tests we can safely import waitFor and use modern and legacy timers interchangeably, but without await.

[dcalhoun]

@thymikee yes, I had reviewed #397 as well in hopes of finding an answer. To reduce the number of variables, I copied the provided tests from RNTL into my test case repository. The new branch (add-rntl-tests) still experiences the below failures. So, I'm thinking something must be a difference in the configuration or package versions?

[dcalhoun]

@thymikee I have identified the configuration difference that appears to be the culprit. The RNTL repository babel.config.js does not include module:metro-react-native-babel-preset. My test case babel.config.js does include module:metro-react-native-babel-preset.

The inclusion of module:metro-react-native-babel-preset is a part of the default React Native template. Adding module:metro-react-native-babel-preset to the RNTL repository causes the tests to begin to fail as I have outlined in my original post.

At this point, I'm not sure if this is a RNTL issue, Jest issue, or a React Native issue. Do you know why module:metro-react-native-babel-preset is not a part of the RNTL repository? Any ideas as to why its inclusion would cause this issue with combining "modern" mock timers and waitFor?

Thanks!

[thymikee]

We don't use Metro babel preset, because we're a Node.js library, not a JSC/Hermes app. You'd need to check on the compiled output to see what's the difference in waitFor. I have no immediate idea what might causing that. Maybe async/await is transpiled by Metro? Or they use custom promise implementation?

[dcalhoun]

@thymikee makes sense. However, given that this library is intended to be used with a JSC/Hermes app, I would think testing in that environment would be ideal for this library.

I'll try to research further. I'm not sure how I'd go about comparing the compiled output Jest holds in-memory. If you have any guidance on that, it'd be appreciated. Thanks.

[thymikee]

jest --showConfig

Then find "cacheDirectory" and you'll see the transformed output.

given that this library is intended to be used with a JSC/Hermes app, I would think testing in that environment would be ideal for this library

We may adjust our Babel config for testing to reflect that, PRs welcome :)

[dcalhoun]

@thymikee I ran the waitFor tests within this repo with and without module:metro-react-native-babel-preset, but I'm not going to pretend to understand what the issue might be in the diff. 🙃 I am definitely not intimately familiar with Babel and how it works. Any assistance you are wiling to provide is appreciated.

It appears that when using module:metro-react-native-babel-preset regenerator is used to manage the async work. So, maybe the issue resides in its usage?

Without module:metro-react-native-babel-preset (Passes)

test('works with fake timers', async () => {
  jest.useFakeTimers('modern');
  const mockFn = jest.fn(() => {
    throw Error('test');
  });

  try {
    (0, _.waitFor)(() => mockFn(), {
      timeout: 400,
      interval: 200
    });
  } catch (e) {// suppress
  }

  jest.advanceTimersByTime(400);
  expect(mockFn).toHaveBeenCalledTimes(3);
});

Full Test File

ce53c85bde85f5c2506a2ba83e183d7f
"use strict";

var _react = _interopRequireDefault(require("react"));

var _reactNative = require("react-native");

var _ = require("..");

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }

class Banana extends _react.default.Component {
  constructor(...args) {
    super(...args);

    _defineProperty(this, "changeFresh", () => {
      this.props.onChangeFresh();
    });
  }

  render() {
    return /*#__PURE__*/_react.default.createElement(_reactNative.View, null, this.props.fresh && /*#__PURE__*/_react.default.createElement(_reactNative.Text, null, "Fresh"), /*#__PURE__*/_react.default.createElement(_reactNative.TouchableOpacity, {
      onPress: this.changeFresh
    }, /*#__PURE__*/_react.default.createElement(_reactNative.Text, null, "Change freshness!")));
  }

}

class BananaContainer extends _react.default.Component {
  constructor(...args) {
    super(...args);

    _defineProperty(this, "state", {
      fresh: false
    });

    _defineProperty(this, "onChangeFresh", async () => {
      await new Promise(resolve => setTimeout(resolve, 300));
      this.setState({
        fresh: true
      });
    });
  }

  render() {
    return /*#__PURE__*/_react.default.createElement(Banana, {
      onChangeFresh: this.onChangeFresh,
      fresh: this.state.fresh
    });
  }

}

afterEach(() => {
  jest.useRealTimers();
});
test('waits for element until it stops throwing', async () => {
  const {
    getByText,
    queryByText
  } = (0, _.render)( /*#__PURE__*/_react.default.createElement(BananaContainer, null));

  _.fireEvent.press(getByText('Change freshness!'));

  expect(queryByText('Fresh')).toBeNull();
  const freshBananaText = await (0, _.waitFor)(() => getByText('Fresh'));
  expect(freshBananaText.props.children).toBe('Fresh');
});
test('waits for element until timeout is met', async () => {
  const {
    getByText
  } = (0, _.render)( /*#__PURE__*/_react.default.createElement(BananaContainer, null));

  _.fireEvent.press(getByText('Change freshness!'));

  await expect((0, _.waitFor)(() => getByText('Fresh'), {
    timeout: 100
  })).rejects.toThrow(); // Async action ends after 300ms and we only waited 100ms, so we need to wait
  // for the remaining async actions to finish

  await (0, _.waitFor)(() => getByText('Fresh'));
});
test('waits for element with custom interval', async () => {
  const mockFn = jest.fn(() => {
    throw Error('test');
  });

  try {
    await (0, _.waitFor)(() => mockFn(), {
      timeout: 400,
      interval: 200
    });
  } catch (e) {// suppress
  }

  expect(mockFn).toHaveBeenCalledTimes(3);
});
test('works with legacy fake timers', async () => {
  jest.useFakeTimers('legacy');
  const mockFn = jest.fn(() => {
    throw Error('test');
  });

  try {
    (0, _.waitFor)(() => mockFn(), {
      timeout: 400,
      interval: 200
    });
  } catch (e) {// suppress
  }

  jest.advanceTimersByTime(400);
  expect(mockFn).toHaveBeenCalledTimes(3);
});
test('works with fake timers', async () => {
  jest.useFakeTimers('modern');
  const mockFn = jest.fn(() => {
    throw Error('test');
  });

  try {
    (0, _.waitFor)(() => mockFn(), {
      timeout: 400,
      interval: 200
    });
  } catch (e) {// suppress
  }

  jest.advanceTimersByTime(400);
  expect(mockFn).toHaveBeenCalledTimes(3);
});
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@flow\nimport React from 'react';\nimport { View, Text, TouchableOpacity } from 'react-native';\nimport { render, fireEvent, waitFor } from '..';\n\nclass Banana extends React.Component<any> {\n  changeFresh = () => {\n    this.props.onChangeFresh();\n  };\n\n  render() {\n    return (\n      <View>\n        {this.props.fresh && <Text>Fresh</Text>}\n        <TouchableOpacity onPress={this.changeFresh}>\n          <Text>Change freshness!</Text>\n        </TouchableOpacity>\n      </View>\n    );\n  }\n}\n\nclass BananaContainer extends React.Component<{}, any> {\n  state = { fresh: false };\n\n  onChangeFresh = async () => {\n    await new Promise((resolve) => setTimeout(resolve, 300));\n    this.setState({ fresh: true });\n  };\n\n  render() {\n    return (\n      <Banana onChangeFresh={this.onChangeFresh} fresh={this.state.fresh} />\n    );\n  }\n}\n\nafterEach(() => {\n  jest.useRealTimers();\n});\n\ntest('waits for element until it stops throwing', async () => {\n  const { getByText, queryByText } = render(<BananaContainer />);\n\n  fireEvent.press(getByText('Change freshness!'));\n\n  expect(queryByText('Fresh')).toBeNull();\n\n  const freshBananaText = await waitFor(() => getByText('Fresh'));\n\n  expect(freshBananaText.props.children).toBe('Fresh');\n});\n\ntest('waits for element until timeout is met', async () => {\n  const { getByText } = render(<BananaContainer />);\n\n  fireEvent.press(getByText('Change freshness!'));\n\n  await expect(\n    waitFor(() => getByText('Fresh'), { timeout: 100 })\n  ).rejects.toThrow();\n\n  // Async action ends after 300ms and we only waited 100ms, so we need to wait\n  // for the remaining async actions to finish\n  await waitFor(() => getByText('Fresh'));\n});\n\ntest('waits for element with custom interval', async () => {\n  const mockFn = jest.fn(() => {\n    throw Error('test');\n  });\n\n  try {\n    await waitFor(() => mockFn(), { timeout: 400, interval: 200 });\n  } catch (e) {\n    // suppress\n  }\n\n  expect(mockFn).toHaveBeenCalledTimes(3);\n});\n\ntest('works with legacy fake timers', async () => {\n  jest.useFakeTimers('legacy');\n\n  const mockFn = jest.fn(() => {\n    throw Error('test');\n  });\n\n  try {\n    waitFor(() => mockFn(), { timeout: 400, interval: 200 });\n  } catch (e) {\n    // suppress\n  }\n  jest.advanceTimersByTime(400);\n\n  expect(mockFn).toHaveBeenCalledTimes(3);\n});\n\ntest('works with fake timers', async () => {\n  jest.useFakeTimers('modern');\n\n  const mockFn = jest.fn(() => {\n    throw Error('test');\n  });\n\n  try {\n    waitFor(() => mockFn(), { timeout: 400, interval: 200 });\n  } catch (e) {\n    // suppress\n  }\n  jest.advanceTimersByTime(400);\n\n  expect(mockFn).toHaveBeenCalledTimes(3);\n});\n"]}

With module:metro-react-native-babel-preset (Fails)

test('works with fake timers', function _callee6() {
  var mockFn;
  return _regenerator.default.async(function _callee6$(_context6) {
    while (1) {
      switch (_context6.prev = _context6.next) {
        case 0:
          jest.useFakeTimers('modern');
          mockFn = jest.fn(function () {
            throw Error('test');
          });

          try {
            (0, _.waitFor)(function () {
              return mockFn();
            }, {
              timeout: 400,
              interval: 200
            });
          } catch (e) {}

          jest.advanceTimersByTime(400);
          expect(mockFn).toHaveBeenCalledTimes(3);

        case 5:
        case "end":
          return _context6.stop();
      }
    }
  }, null, null, null, Promise);
});

Full Test File

7fc2847285e7ee92e202d0101776c7b0
var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");

var _regenerator = _interopRequireDefault(require("@babel/runtime/regenerator"));

var _classCallCheck2 = _interopRequireDefault(require("@babel/runtime/helpers/classCallCheck"));

var _createClass2 = _interopRequireDefault(require("@babel/runtime/helpers/createClass"));

var _assertThisInitialized2 = _interopRequireDefault(require("@babel/runtime/helpers/assertThisInitialized"));

var _inherits2 = _interopRequireDefault(require("@babel/runtime/helpers/inherits"));

var _possibleConstructorReturn2 = _interopRequireDefault(require("@babel/runtime/helpers/possibleConstructorReturn"));

var _getPrototypeOf2 = _interopRequireDefault(require("@babel/runtime/helpers/getPrototypeOf"));

var _defineProperty2 = _interopRequireDefault(require("@babel/runtime/helpers/defineProperty"));

var _react = _interopRequireDefault(require("react"));

var _reactNative = require("react-native");

var _ = require("..");

function _createSuper(Derived) { var hasNativeReflectConstruct = _isNativeReflectConstruct(); return function _createSuperInternal() { var Super = (0, _getPrototypeOf2.default)(Derived), result; if (hasNativeReflectConstruct) { var NewTarget = (0, _getPrototypeOf2.default)(this).constructor; result = Reflect.construct(Super, arguments, NewTarget); } else { result = Super.apply(this, arguments); } return (0, _possibleConstructorReturn2.default)(this, result); }; }

function _isNativeReflectConstruct() { if (typeof Reflect === "undefined" || !Reflect.construct) return false; if (Reflect.construct.sham) return false; if (typeof Proxy === "function") return true; try { Date.prototype.toString.call(Reflect.construct(Date, [], function () {})); return true; } catch (e) { return false; } }

var Banana = function (_React$Component) {
  (0, _inherits2.default)(Banana, _React$Component);

  var _super = _createSuper(Banana);

  function Banana() {
    var _this;

    (0, _classCallCheck2.default)(this, Banana);

    for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
      args[_key] = arguments[_key];
    }

    _this = _super.call.apply(_super, [this].concat(args));
    (0, _defineProperty2.default)((0, _assertThisInitialized2.default)(_this), "changeFresh", function () {
      _this.props.onChangeFresh();
    });
    return _this;
  }

  (0, _createClass2.default)(Banana, [{
    key: "render",
    value: function render() {
      return _react.default.createElement(_reactNative.View, null, this.props.fresh && _react.default.createElement(_reactNative.Text, null, "Fresh"), _react.default.createElement(_reactNative.TouchableOpacity, {
        onPress: this.changeFresh
      }, _react.default.createElement(_reactNative.Text, null, "Change freshness!")));
    }
  }]);
  return Banana;
}(_react.default.Component);

var BananaContainer = function (_React$Component2) {
  (0, _inherits2.default)(BananaContainer, _React$Component2);

  var _super2 = _createSuper(BananaContainer);

  function BananaContainer() {
    var _this2;

    (0, _classCallCheck2.default)(this, BananaContainer);

    for (var _len2 = arguments.length, args = new Array(_len2), _key2 = 0; _key2 < _len2; _key2++) {
      args[_key2] = arguments[_key2];
    }

    _this2 = _super2.call.apply(_super2, [this].concat(args));
    (0, _defineProperty2.default)((0, _assertThisInitialized2.default)(_this2), "state", {
      fresh: false
    });
    (0, _defineProperty2.default)((0, _assertThisInitialized2.default)(_this2), "onChangeFresh", function _callee() {
      return _regenerator.default.async(function _callee$(_context) {
        while (1) {
          switch (_context.prev = _context.next) {
            case 0:
              _context.next = 2;
              return _regenerator.default.awrap(new Promise(function (resolve) {
                return setTimeout(resolve, 300);
              }));

            case 2:
              _this2.setState({
                fresh: true
              });

            case 3:
            case "end":
              return _context.stop();
          }
        }
      }, null, null, null, Promise);
    });
    return _this2;
  }

  (0, _createClass2.default)(BananaContainer, [{
    key: "render",
    value: function render() {
      return _react.default.createElement(Banana, {
        onChangeFresh: this.onChangeFresh,
        fresh: this.state.fresh
      });
    }
  }]);
  return BananaContainer;
}(_react.default.Component);

afterEach(function () {
  jest.useRealTimers();
});
test('waits for element until it stops throwing', function _callee2() {
  var _render, getByText, queryByText, freshBananaText;

  return _regenerator.default.async(function _callee2$(_context2) {
    while (1) {
      switch (_context2.prev = _context2.next) {
        case 0:
          _render = (0, _.render)(_react.default.createElement(BananaContainer, null)), getByText = _render.getByText, queryByText = _render.queryByText;

          _.fireEvent.press(getByText('Change freshness!'));

          expect(queryByText('Fresh')).toBeNull();
          _context2.next = 5;
          return _regenerator.default.awrap((0, _.waitFor)(function () {
            return getByText('Fresh');
          }));

        case 5:
          freshBananaText = _context2.sent;
          expect(freshBananaText.props.children).toBe('Fresh');

        case 7:
        case "end":
          return _context2.stop();
      }
    }
  }, null, null, null, Promise);
});
test('waits for element until timeout is met', function _callee3() {
  var _render2, getByText;

  return _regenerator.default.async(function _callee3$(_context3) {
    while (1) {
      switch (_context3.prev = _context3.next) {
        case 0:
          _render2 = (0, _.render)(_react.default.createElement(BananaContainer, null)), getByText = _render2.getByText;

          _.fireEvent.press(getByText('Change freshness!'));

          _context3.next = 4;
          return _regenerator.default.awrap(expect((0, _.waitFor)(function () {
            return getByText('Fresh');
          }, {
            timeout: 100
          })).rejects.toThrow());

        case 4:
          _context3.next = 6;
          return _regenerator.default.awrap((0, _.waitFor)(function () {
            return getByText('Fresh');
          }));

        case 6:
        case "end":
          return _context3.stop();
      }
    }
  }, null, null, null, Promise);
});
test('waits for element with custom interval', function _callee4() {
  var mockFn;
  return _regenerator.default.async(function _callee4$(_context4) {
    while (1) {
      switch (_context4.prev = _context4.next) {
        case 0:
          mockFn = jest.fn(function () {
            throw Error('test');
          });
          _context4.prev = 1;
          _context4.next = 4;
          return _regenerator.default.awrap((0, _.waitFor)(function () {
            return mockFn();
          }, {
            timeout: 400,
            interval: 200
          }));

        case 4:
          _context4.next = 8;
          break;

        case 6:
          _context4.prev = 6;
          _context4.t0 = _context4["catch"](1);

        case 8:
          expect(mockFn).toHaveBeenCalledTimes(3);

        case 9:
        case "end":
          return _context4.stop();
      }
    }
  }, null, null, [[1, 6]], Promise);
});
test('works with legacy fake timers', function _callee5() {
  var mockFn;
  return _regenerator.default.async(function _callee5$(_context5) {
    while (1) {
      switch (_context5.prev = _context5.next) {
        case 0:
          jest.useFakeTimers('legacy');
          mockFn = jest.fn(function () {
            throw Error('test');
          });

          try {
            (0, _.waitFor)(function () {
              return mockFn();
            }, {
              timeout: 400,
              interval: 200
            });
          } catch (e) {}

          jest.advanceTimersByTime(400);
          expect(mockFn).toHaveBeenCalledTimes(3);

        case 5:
        case "end":
          return _context5.stop();
      }
    }
  }, null, null, null, Promise);
});
test('works with fake timers', function _callee6() {
  var mockFn;
  return _regenerator.default.async(function _callee6$(_context6) {
    while (1) {
      switch (_context6.prev = _context6.next) {
        case 0:
          jest.useFakeTimers('modern');
          mockFn = jest.fn(function () {
            throw Error('test');
          });

          try {
            (0, _.waitFor)(function () {
              return mockFn();
            }, {
              timeout: 400,
              interval: 200
            });
          } catch (e) {}

          jest.advanceTimersByTime(400);
          expect(mockFn).toHaveBeenCalledTimes(3);

        case 5:
        case "end":
          return _context6.stop();
      }
    }
  }, null, null, null, Promise);
});
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@flow\nimport React from 'react';\nimport { View, Text, TouchableOpacity } from 'react-native';\nimport { render, fireEvent, waitFor } from '..';\n\nclass Banana extends React.Component<any> {\n  changeFresh = () => {\n    this.props.onChangeFresh();\n  };\n\n  render() {\n    return (\n      <View>\n        {this.props.fresh && <Text>Fresh</Text>}\n        <TouchableOpacity onPress={this.changeFresh}>\n          <Text>Change freshness!</Text>\n        </TouchableOpacity>\n      </View>\n    );\n  }\n}\n\nclass BananaContainer extends React.Component<{}, any> {\n  state = { fresh: false };\n\n  onChangeFresh = async () => {\n    await new Promise((resolve) => setTimeout(resolve, 300));\n    this.setState({ fresh: true });\n  };\n\n  render() {\n    return (\n      <Banana onChangeFresh={this.onChangeFresh} fresh={this.state.fresh} />\n    );\n  }\n}\n\nafterEach(() => {\n  jest.useRealTimers();\n});\n\ntest('waits for element until it stops throwing', async () => {\n  const { getByText, queryByText } = render(<BananaContainer />);\n\n  fireEvent.press(getByText('Change freshness!'));\n\n  expect(queryByText('Fresh')).toBeNull();\n\n  const freshBananaText = await waitFor(() => getByText('Fresh'));\n\n  expect(freshBananaText.props.children).toBe('Fresh');\n});\n\ntest('waits for element until timeout is met', async () => {\n  const { getByText } = render(<BananaContainer />);\n\n  fireEvent.press(getByText('Change freshness!'));\n\n  await expect(\n    waitFor(() => getByText('Fresh'), { timeout: 100 })\n  ).rejects.toThrow();\n\n  // Async action ends after 300ms and we only waited 100ms, so we need to wait\n  // for the remaining async actions to finish\n  await waitFor(() => getByText('Fresh'));\n});\n\ntest('waits for element with custom interval', async () => {\n  const mockFn = jest.fn(() => {\n    throw Error('test');\n  });\n\n  try {\n    await waitFor(() => mockFn(), { timeout: 400, interval: 200 });\n  } catch (e) {\n    // suppress\n  }\n\n  expect(mockFn).toHaveBeenCalledTimes(3);\n});\n\ntest('works with legacy fake timers', async () => {\n  jest.useFakeTimers('legacy');\n\n  const mockFn = jest.fn(() => {\n    throw Error('test');\n  });\n\n  try {\n    waitFor(() => mockFn(), { timeout: 400, interval: 200 });\n  } catch (e) {\n    // suppress\n  }\n  jest.advanceTimersByTime(400);\n\n  expect(mockFn).toHaveBeenCalledTimes(3);\n});\n\ntest('works with fake timers', async () => {\n  jest.useFakeTimers('modern');\n\n  const mockFn = jest.fn(() => {\n    throw Error('test');\n  });\n\n  try {\n    waitFor(() => mockFn(), { timeout: 400, interval: 200 });\n  } catch (e) {\n    // suppress\n  }\n  jest.advanceTimersByTime(400);\n\n  expect(mockFn).toHaveBeenCalledTimes(3);\n});\n"]}

[mikeduminy]

Just hit this problem now as I was migrating our app to RN 0.63. I had a look at how other testing-librarys solve it and it seems like they check if jest fake timers are set and run different logic here, while also capturing the global timer functions before they are overridden and then use these in their waitFor implementation.

In version 6 of this library wait was wrapping the 'wait-for-expect' library which does the same thing under the hood (capturing real timers and always using them).

Not sure if this is a known and intended consequence of the deprecation of the previous repo and whatever rewriting took place, but it would be SUPER good to have it in this repo so we don't have to change tonnes of code. However, primarily I think it is unreasonable that using timer mocks in our test would affect the test library code and so I would strongly request that this library ensures it is unaffected by any user-land settings.

If the maintainers agree with this direction but don't have the time to do this any time soon then I can take over the implementation. Please let me know.

[thymikee]

Would love to merge a PR fixing that for good 👍

[mikeduminy]

Okay it looks like the general approach followed by wait-for-expect to capture the global timer funcs before they get mocked works, but it has highlighted a problem with the 'modern' timer mocks which is caused partially by the 'react-native' preset polyfilling global.promise and partially by the new timer mocks mocking process.nextTick. I've written most of the code for the first bit but to make it work with modern timers we need to patch a line in '@jest/fake-timers'.

Will send a PR tomorrow.

[mikeduminy]

PR sent, please have a look.