Synchronous tests don't time out

🐛 Bug Report

jest.setTimeout(timeout) does not time out for synchronous tests.

To Reproduce

run

  it('times out', () => {
    const startTime = new Date().getTime();
    while (new Date().getTime() - startTime < 10000) {
      // wait
    }
  });

Expected behavior

The test times out.

Link to repl or repo

https://repl.it/@gitlab_winnie/jestsetTimeouttimeout-for-synchronous-tests

Run npx envinfo --preset jest

  Binaries:
    Node: 9.0.0 - ~/.nvm/versions/node/v9.0.0/bin/node
    Yarn: 1.7.0 - /usr/local/bin/yarn
    npm: 5.8.0 - ~/.nvm/versions/node/v9.0.0/bin/npm
  npmPackages:
    jest: ^23.5.0 => 23.5.0

[ghost]

but I’m still not sure if enabling it by default would be useful for most users

@rubennorte Maybe we can create a separate follow-up issue to discuss whether this should become the default behavior? Then people can throw their 👍s and 👎s at it after trying it out. 😃

Personally I wouldn’t mind if it is not the default but having it at all would be a big help.

[slombardo]

I am able repro this. I also was able to narrow it down (in my case) to nested long running for loops:

describe("timeout tests", () => {
    test('Times out properly', (done) => {
        setTimeout(done, 10000);
    }, 2000);

    test('Times out properly', (done) => {
        for (let i = 0; i < 937351770; i++) {
        }
    }, 2000);

    test('Does not time out at all, just spins', (done) => {
        for (let i = 0; i < 937351770; i++) {
            for (let j = 0; j < 937351770; j++) {

            }
        }
    }, 2000);
});