node/test/parallel/test-stream-readable-resumeScheduled.js

'use strict';
const common = require('../common');

// Testing Readable Stream resumeScheduled state

const assert = require('assert');
const { Readable, Writable } = require('stream');

{
  // pipe() test case
  const r = new Readable({ read() {} });
  const w = new Writable();

  // resumeScheduled should start = `false`.
  assert.strictEqual(r._readableState.resumeScheduled, false);

  // calling pipe() should change the state value = true.
  r.pipe(w);
  assert.strictEqual(r._readableState.resumeScheduled, true);

  process.nextTick(common.mustCall(() => {
    assert.strictEqual(r._readableState.resumeScheduled, false);
  }));
}

{
  // 'data' listener test case
  const r = new Readable({ read() {} });

  // resumeScheduled should start = `false`.
  assert.strictEqual(r._readableState.resumeScheduled, false);

  r.push(Buffer.from([1, 2, 3]));

  // adding 'data' listener should change the state value
  r.on('data', common.mustCall(() => {
    assert.strictEqual(r._readableState.resumeScheduled, false);
  }));
  assert.strictEqual(r._readableState.resumeScheduled, true);

  process.nextTick(common.mustCall(() => {
    assert.strictEqual(r._readableState.resumeScheduled, false);
  }));
}

{
  // resume() test case
  const r = new Readable({ read() {} });

  // resumeScheduled should start = `false`.
  assert.strictEqual(r._readableState.resumeScheduled, false);

  // Calling resume() should change the state value.
  r.resume();
  assert.strictEqual(r._readableState.resumeScheduled, true);

  r.on('resume', common.mustCall(() => {
    // The state value should be `false` again
    assert.strictEqual(r._readableState.resumeScheduled, false);
  }));

  process.nextTick(common.mustCall(() => {
    assert.strictEqual(r._readableState.resumeScheduled, false);
  }));
}