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import { expect } from 'chai';import { stub } from 'sinon';import { fallback, handleAll } from './Policy';
describe('FallbackPolicy', () => {  it('does not fall back when not necessary', async () => {    const result = await fallback(handleAll, 'error').execute(() => 'ok');    expect(result).to.equal('ok');  });
  it('returns a fallback and emits an error if necessary', async () => {    const policy = fallback(handleAll, 'error');    const onFallback = stub();    policy.onFailure(onFallback);
    const error = new Error('oh no!');    const result = await policy.execute(() => {      throw error;    });    expect(result).to.equal('error');    expect(onFallback).calledWith({      reason: { error },      handled: true,      duration: onFallback.args[0]?.[0].duration,    });  });
  it('links parent cancellation token', async () => {    const parent = new AbortController();    await fallback(handleAll, 'error').execute(({ signal }) => {      expect(signal.aborted).to.be.false;      parent.abort();      expect(signal.aborted).to.be.true;    }, parent.signal);  });});