Vitest: Incorrect filename when running concurrently

[HalfdanJ]

When using jest-image-snapshots in vitest, the naming of the snapshot files are incorrect when a test suite is run concurrently (describe.concurrent().

Instead of getting the name of each test, it instead gets the name of the last test in the suite, appended with an index, and the order depends on which tests finish first.

I'm unsure if this is a vitest issue or jest-image-snapshot issue.

[vinnymac]

This is likely related to #181.

I am experiencing a similar issue with test.concurrent.for where the tests fail on the second run every time. test.for does not behave this way. If I replace toMatchImageSnapshot with toMatchSnapshot it also works without issue.

This leads me to believe that the global state referenced in #181 means this library does not currently support concurrent testing. While it'd be nice if the README mentioned this, ideally this would get fixed internally, perhaps to match the behavior of toMatchSnapshot. AsyncLocalStorage may be one solution for example 🤔

[martinwcf]

If anyone else ends up here because vitest + jest-image-snapshot doens't work with concurrency on, a workaround can be:

test("task name", async (ctx) => {
    let counter = 0;
    const customSnapshotIdentifier = (/* Can't trust any parameter when concurrency is on */) => {
        return `${ctx.task.name.replace(/\s/g, "-")}-${++counter}`;
    };

    expect(await something1()).toMatchImageSnapshot({ customSnapshotIdentifier });
    expect(await something2()).toMatchImageSnapshot({ customSnapshotIdentifier });

    //...
});

It's a minimal example, wrap that in any way you want.