Plugin: how to get calling test file's info

[jacob-orbiit]

I'm trying to create a snapshot plugin for chai (and would be happy to contribute it); snapshots live adjacent to the test file itself. The docs related to creating plugins are rather…sparse, and I don't see anything related to that, and the info related to getting the actual value seems to be incorrect (I just get undefined).

For example:

// setup.mjs
chai.use(myChaiSnapshot);

export default function chaiSnapshotPlugin(chai, utils) {
  chai.Assertion.addChainableMethod('matchSnapshot', function matchSnapshot(...args) {
    const obj = utils.flag(this, 'string');
    console.log({ this: this, obj }, ...args);
  });
}

it('should contain debug into in dev mode', () => {
  expect('<div>debug: foo, bar, baz</div>').to.matchSnapshot();
});

{
  this: Assertion {
    __flags: [Object: null prototype] {
      ssfi: [Function: chainableMethodWrapper] Assertion,
      lockSsfi: undefined,
      object: undefined,
      message: undefined
    }
  },
  obj: undefined
}

I could pass import.meta.url to matchSnapshot() every time, but that would very inelegant.