Function runTest

test/parallel/test-stream2-readable-wrap.js:28–93

(highWaterMark, objectMode, produce)

const EE = require('events').EventEmitter;

function runTest(highWaterMark, objectMode, produce) {

  const old = new EE();
  const r = new Readable({ highWaterMark, objectMode });
  assert.strictEqual(r, r.wrap(old));

  r.on('end', common.mustCall());

  old.pause = function() {
    old.emit('pause');
    flowing = false;
  };

  old.resume = function() {
    old.emit('resume');
    flow();
  };

  // Make sure pause is only emitted once.
  let pausing = false;
  r.on('pause', common.mustCallAtLeast(() => {
    assert.strictEqual(pausing, false);
    pausing = true;
    process.nextTick(() => {
      pausing = false;
    });
  }));

  let flowing;
  let chunks = 10;
  let oldEnded = false;
  const expected = [];
  function flow() {
    flowing = true;
    while (flowing && chunks-- > 0) {
      const item = produce();
      expected.push(item);
      old.emit('data', item);
    }
    if (chunks <= 0) {
      oldEnded = true;
      old.emit('end');
    }
  }

  const w = new Writable({ highWaterMark: highWaterMark * 2,
                           objectMode });
  const written = [];
  w._write = function(chunk, encoding, cb) {
    written.push(chunk);
    setTimeout(cb, 1);
  };

  w.on('finish', common.mustCall(function() {
    performAsserts();
  }));

  r.pipe(w);