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import { expect } from 'chai';import { stub } from 'sinon';import { ConsecutiveBreaker } from './breaker/Breaker';import { BrokenCircuitError } from './errors/Errors';import {  circuitBreaker,  fallback,  handleAll,  handleResultType,  handleType,  noop,  retry,  timeout,  usePolicy,  wrap,} from './Policy';import { IRetryContext } from './RetryPolicy';import { TimeoutStrategy } from './TimeoutPolicy';
class MyError1 extends Error {}class MyError2 extends Error {}class MyError3 extends Error {}
const assertNever = (_value: never) => {  throw new Error('unreachable');};
describe('Policy', () => {  it('wraps', async () => {    const policy = wrap(      retry(handleType(MyError1), { maxAttempts: 3 }),      circuitBreaker(handleAll, { halfOpenAfter: 100, breaker: new ConsecutiveBreaker(2) }),    );
    // should retry and break the circuit    await expect(policy.execute(stub().throws(new MyError1()))).to.be.rejectedWith(      BrokenCircuitError,    );  });
  it('wraps and keeps correct types', async () => {    const policies = [      retry(handleAll, { maxAttempts: 2 }),      circuitBreaker(handleAll, { halfOpenAfter: 100, breaker: new ConsecutiveBreaker(2) }),      fallback(handleAll, 'foo'),      timeout(1000, TimeoutStrategy.Aggressive),      noop,    ] as const;    const policy = wrap(...policies);
    expect(policy.wrapped).to.deep.equal(policies);
    const result = await policy.execute(context => {      expect(context.signal).to.be.an.instanceOf(AbortSignal);      expect(context.attempt).to.equal(0);      return 1234;    });
    switch (typeof result) {      case 'string':        result.toUpperCase();        break;      case 'number':        Math.pow(result, 2);        break;      default:        assertNever(result);    }  });
  it('applies error filters', async () => {    const fn = stub()      .onCall(0)      .throws(new MyError1())      .onCall(1)      .throws(new MyError2())      .onCall(2)      .throws(new MyError3('foo'))      .onCall(3)      .throws(new Error('potato'))      .onCall(4)      .throws(new MyError3('bar'));
    await expect(      retry(        handleType(MyError1)          .orType(MyError2)          .orType(MyError3, e => e.message === 'foo')          .orWhen(e => e.message === 'potato'),        { maxAttempts: 10 },      ).execute(fn),    ).to.be.rejectedWith(MyError3, 'bar');
    expect(fn).to.have.callCount(5);  });
  it('applies result filters', async () => {    const fn = stub()      .onCall(0)      .returns(new MyError1())      .onCall(1)      .returns(new MyError2())      .onCall(2)      .returns(new MyError3('foo'))      .onCall(3)      .returns('potato')      .onCall(4)      .returns('ok!');
    expect(      await retry(        handleResultType(MyError1)          .orResultType(MyError2)          .orResultType(MyError3, e => e.message === 'foo')          .orWhenResult(e => e === 'potato'),        { maxAttempts: 10 },      ).execute(fn),    ).to.equal('ok!');
    expect(fn).to.have.callCount(5);  });
  it('applies use', async () => {    class Calculator {      @usePolicy(retry(handleAll, { maxAttempts: 5 }))      public double(n: number, context: IRetryContext) {        if (context!.attempt < 2) {          throw new Error('failed');        }
        return { n: n * 2, ...context! };      }    }
    const c = new Calculator();    // @ts-ignore    const r = await c.double(2);    expect(r).to.deep.equal({      n: 4,      signal: r.signal,      attempt: 2,    });  });
  it('uses cancellation token in use', async () => {    class Calculator {      @usePolicy(retry(handleAll, { maxAttempts: 5 }))      public double(n: number, context: IRetryContext) {        expect(n).to.equal(2);        expect(context.signal.aborted).to.be.false;        cts.abort();        expect(context.signal.aborted).to.be.true;        return n * 2;      }    }
    const cts = new AbortController();    const c = new Calculator();    // @ts-ignore    expect(await c.double(2, cts.signal)).to.equal(4);  });});