Race condition on snapshots when a test timeouts

🐛 Bug Report

When I have two tests that use snapshots, if the first timeouts, the content of the first test will be in the snapshot of the second test

To Reproduce

I have made a repository that reproduces the issue :

• Repository : https://github.com/onigoetz/jest-race-condition-repro
• Github Actions failed jest run : https://github.com/onigoetz/jest-race-condition-repro/runs/218697180

The code

/**
 * The Dummy code to test
 * Just a function that returns the first argument after 600ms
 * @param {*} content
 */
function longRunningFunction(content) {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve(content);
    }, 600);
  });
}

// This is only needed in the test repro
// If the snapshots don't exist, leave the time for them to be created
// If they exist, fail the test on purpose
const fs = require("fs");
const path = require("path");
const snapshotFile = `${path.basename(__filename)}.snap`;
const snapshotPath = path.dirname(process.cwd(), "__snapshots__", snapshotFile);
if (fs.existsSync(snapshotPath)) {
  jest.setTimeout(400);
}

// The tests
it("Runs a first test", async () => {
  expect(
    await longRunningFunction("Content of the first test")
  ).toMatchSnapshot();
});

it("Runs a second test", async () => {
  expect(
    await longRunningFunction("Content of the second test")
  ).toMatchSnapshot();
});

Run this code twice to see the error

Output

  ● Runs a second test

    expect(received).toMatchSnapshot()

    Snapshot name: `Runs a second test 1`

    Snapshot: "Content of the second test"
    Received: "Content of the first test"

      27 |   expect(
      28 |     await longRunningFunction("Content of the first test")
    > 29 |   ).toMatchSnapshot();

You see that it’s the call to snapshot from the first test that ends in the second test.

Expected behavior

The content of the first test should be in the second snapshot The content of the second test should be in the second snapshot

Link to repro

• Repository : https://github.com/onigoetz/jest-race-condition-repro
• Github Actions failed jest run : https://github.com/onigoetz/jest-race-condition-repro/runs/218697180

envinfo

  System:
    OS: Linux 4.15 Ubuntu 18.04.3 LTS (Bionic Beaver)
    CPU: (8) x64 Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz
  Binaries:
    Node: 8.16.0 - ~/.nvm/versions/node/v8.16.0/bin/node
    Yarn: 1.17.3 - /usr/bin/yarn
    npm: 6.4.1 - ~/.nvm/versions/node/v8.16.0/bin/npm
  npmPackages:
    jest: ^24.9.0 => 24.9.0 

It’s also the same on GitHub actions on node 8, 10 and 12

[onigoetz]

Stale maybe, but the bug is still present in Jest 27 : https://github.com/onigoetz/jest-race-condition-repro

[github-actions[bot]]

This issue is stale because it has been open for 1 year with no activity. Remove stale label or comment or this will be closed in 14 days.