How to run concurrent tests in Jest with multiple tests per request?

Question

I'd like to run my Jest tests concurrently, but I'm having issues with one scenario:

I'm testing the results on an endpoint, and I want to test multiple things about it. So in my beforeAll function, I make the request and store the response, and then I test the response in multiple tests. This works fine synchronously, but when I make the tests concurrent, it no longer lets you pass a variable into the test, so it's a no go. Alternatively, I can put the request in the test itself and then expect many things about the response, but then I don't have the granularity to see what went wrong if something fails.

Is there any solution for this scenario?

This works:

let data;
beforeAll(async () => {
    data = await getDataFromRequest();
}
it('value1 should be truthy', () => {
    expect(data.value1).toBeTruthy();
}
it('value2 should be truthy', () => {
    expect(data.value2).toBeTruthy();
}

This also works:

it.concurrent('data should have correct values', async () => {
    const data = await getDataFromRequest();
    expect(data.value1).toBeTruthy();
    expect(data.value2).toBeTruthy();
}

But what I want is:

let data;
beforeAll(async () => {
    data = await getDataFromRequest();
}
it.concurrent('value1 should be truthy', () => {
    expect(data.value1).toBeTruthy();
}
it.concurrent('value2 should be truthy', () => {
    expect(data.value2).toBeTruthy();
}

Answer 1

Seems worth pointing out, that there is also a discussion about this in a jest issue: https://github.com/facebook/jest/issues/4281

Gist of it: It doesn't work that way and isn't planned. Possible workaround:

const dataPromise = getSomeDataPromise();

test.concurrent('one', async () => {
  const data = await dataPromise;
});

test.concurrent('two', async () => {
  const data = await dataPromise;
});

Answer 2

Was having same issue when doing browser testing with Playwright where one test suite only requires one instance of browser. Had to wrap it with a Promise with setInterval. In your case it should be like below:

let data;

beforeAll(async () => {
    data = await getDataFromRequest();
}
test.concurrent('value1 should be truthy', async () => {
    await waitForData();
    expect(data.value1).toBeTruthy();
}
test.concurrent('value2 should be truthy', async () => {
    await waitForData();
    expect(data.value2).toBeTruthy();
}

/**
 * @param {number} interval -  the interval to check data availability
 * @param {number} timeout -  the overall timeout value
 * @return Promise of your data OR reject if timeout.
 */
function waitForData(interval = 500, timeout = 5000){
  let acc = 0; // time accumulation
  return new Promise((resolve, reject) => {
    const i = setInterval(() => {
      acc += interval;
      if (data) {
        clearInterval(i);
        resolve(data);
      }
      if (acc > timeout) {
        clearInterval(i);
        reject();
      }
    }, interval);
  });
}

So you just need to assign the proper check interval and timeout which should be long enough for your data asycn call to come back.