The "BeforeAll" works later than "it.concurrent", but must work before

[Dmytro-Komaryst]

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();
}

Additional check (the BeforeAll worked after test.concurrent)

describe('', () => {

    beforeAll(() => {
        console.log('start beforeAll') 
    })

    it.concurrent('', async () => {
        console.log('start it.concurrent')
        expect(1).toBe(1)
    })
})

Result:
$ jest
PASS ..\1.test.js
√

Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 1.938s
Ran all test suites.
console.log ..\1.test.js:8
start it.concurrent

console.log ..\1.test.js:4
start beforeAll

[aaronabramov]

that's not possible right now. test.concurrent is very complex and there's tons of things that won't work with it.
for your specific case you can do something like this:

const dataPromise = getSomeDataPromise();

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

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

this way they'll wait on the same promise that will be executed before everything

[jeffijoe]

@aaronabramov are there any plans on supporting it though? How about afterAll, will it execute in an unexpected order as well?

[aaronabramov]

@jeffijoe not in the nearest future.
afterAll should work as expected though, because it'll wait for all tests to be completely done before it runs

[hemanta8841]

@aaronabramov Is this issue added to backlog ? appreciate your response

[yxliang01]

I am wondering why test.concurrent is not shown in the documentation at https://jestjs.io/docs/en/api . Is it no longer available?

[techieshark]

@yxliang01 I believe it simply hasn't been documented there. It is mentioned here, however: https://jestjs.io/docs/en/cli#maxconcurrency-num

--maxConcurrency=
Prevents Jest from executing more than the specified amount of tests at the same time. Only affects tests that use test.concurrent.

[yarulan]

Why is this closed if it's not fixed?

[gselsidi]

obviously cause facebook, jest literally feels like it's dead.

[tobiasfeil]

Issue persists, please reopen

[github-actions]

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