// `navigator.locks` for the unit tests, which run on node, where there is none.
//
// One lock per name: granted in the order it was asked for, and let go when
// the callback settles, whether it resolved or rejected. That is what the
// browser's own does for the one call the extension makes,
// `navigator.locks.request(name, callback)`. Every module a test file loads
// shares it, as every page of the extension and its background share the
// browser's.
//
// Run before each test file by `setupFiles` in package.json.

// For each name, a promise that settles once the last request for it has
// let the lock go.
const released = new Map();

function request(name, callback) {
    const previous = released.get(name) || Promise.resolve();
    const result = previous.then(() => callback({ name, mode: "exclusive" }));
    released.set(
        name,
        result.catch(() => {}),
    );
    return result;
}

globalThis.navigator = { locks: { request } };