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import { expect } from 'chai';import { promisify } from 'util';import { abortedSignal } from './common/abort';import { defer } from './common/defer';import { BulkheadRejectedError } from './errors/BulkheadRejectedError';import { TaskCancelledError } from './errors/Errors';import { bulkhead } from './Policy';
const delay = promisify(setTimeout);
describe('Bulkhead', () => {  let order: string[] = [];  let fnIndex = 0;  beforeEach(() => {    order = [];    fnIndex = 0;  });
  const makeFn = () => {    const index = fnIndex++;    return async () => {      order.push(`${index}: enter`);      await delay(index * 2);      order.push(`${index}: exit`);      return index;    };  };
  const makeFns = (count: number) => {    const out: Array<() => void> = [];    for (let i = 0; i < count; i++) {      out.push(makeFn());    }    return out;  };
  it('rejects calls after limit is hit', async () => {    const b = bulkhead(2);    const funcs = makeFns(3);    const output = funcs.map(fn => b.execute(fn));
    await Promise.all([      expect(output[0]).to.eventually.equal(0),      expect(output[1]).to.eventually.equal(1),      expect(output[2]).to.be.rejectedWith(BulkheadRejectedError),    ]);
    expect(order).to.deep.equal(['0: enter', '1: enter', '0: exit', '1: exit']);  });
  it('queues requests, and rejects after queue limit', async () => {    const b = bulkhead(2, 2);    const funcs = makeFns(5);    const output = funcs.map(fn => b.execute(fn));
    await Promise.all([      expect(output[0]).to.eventually.equal(0),      expect(output[1]).to.eventually.equal(1),      expect(output[2]).to.eventually.equal(2),      expect(output[3]).to.eventually.equal(3),      expect(output[4]).to.be.rejectedWith(BulkheadRejectedError),    ]);
    expect(order).to.deep.equal([      '0: enter',      '1: enter',      '0: exit',      '2: enter',      '1: exit',      '3: enter',      '2: exit',      '3: exit',    ]);  });
  it('maintains proper state', async () => {    const b = bulkhead(2, 2);    const defer1 = defer();    const defer2 = defer();    const defer3 = defer();    const defer4 = defer();
    expect(b.queueSlots).to.equal(2);    expect(b.executionSlots).to.equal(2);
    const out1 = b.execute(() => defer1.promise);    expect(b.queueSlots).to.equal(2);    expect(b.executionSlots).to.equal(1);
    const out2 = b.execute(() => defer2.promise);    expect(b.queueSlots).to.equal(2);    expect(b.executionSlots).to.equal(0);
    const out3 = b.execute(() => defer3.promise);    expect(b.queueSlots).to.equal(1);    expect(b.executionSlots).to.equal(0);
    const out4 = b.execute(() => defer4.promise);    expect(b.queueSlots).to.equal(0);    expect(b.executionSlots).to.equal(0);
    defer1.resolve(undefined);    await out1;    expect(b.executionSlots).to.equal(0);    expect(b.queueSlots).to.equal(1);
    defer2.resolve(undefined);    await out2;    expect(b.executionSlots).to.equal(0);    expect(b.queueSlots).to.equal(2);
    defer3.resolve(undefined);    await out3;    expect(b.executionSlots).to.equal(1);    expect(b.queueSlots).to.equal(2);
    defer4.resolve(undefined);    await out4;    expect(b.executionSlots).to.equal(2);    expect(b.queueSlots).to.equal(2);  });
  it('links parent cancellation token', async () => {    const b = bulkhead(1, Infinity);    const todo: Array<PromiseLike<void>> = [];    for (let i = 0; i < 3; i++) {      const parent = new AbortController();      todo.push(        b.execute(async ({ signal }) => {          await delay(1);          expect(signal.aborted).to.be.false;          parent.abort();          expect(signal.aborted).to.be.true;        }, parent.signal),      );    }
    // initially cancelled    todo.push(      expect(        b.execute(() => {          throw new Error('expected not to call');        }, abortedSignal),      ).to.be.rejectedWith(TaskCancelledError),    );
    // cancelled by the time it gets executed    const cancelledCts = new AbortController();    setTimeout(() => cancelledCts.abort(), 2);    todo.push(      expect(        b.execute(() => {          throw new Error('expected not to call');        }, cancelledCts.signal),      ).to.be.rejectedWith(TaskCancelledError),    );
    await Promise.all(todo);  });});