text: 'use strict';
  const common = require('../common');
  const assert = require('assert');
  const Readable = require('stream').Readable;
  
  const readable = new Readable({
    read: () => {}
  });
  
  // Initialized to false.
  assert.strictEqual(readable._readableState.needReadable, false);
  
  readable.on('readable', common.mustCall(() => {
    // When the readable event fires, needReadable is reset.
    assert.strictEqual(readable._readableState.needReadable, false);
    readable.read();
  }));
  
  // If a readable listener is attached, then a readable event is needed.
  assert.strictEqual(readable._readableState.needReadable, true);
  
  readable.push('foo');
  readable.push(null);
  
  readable.on('end', common.mustCall(() => {
    // No need to emit readable anymore when the stream ends.
    assert.strictEqual(readable._readableState.needReadable, false);
  }));
  
  const asyncReadable = new Readable({
    read: () => {}
  });
  
  asyncReadable.on('readable', common.mustCall(() => {
    if (asyncReadable.read() !== null) {
      // After each read(), the buffer is empty.
      // If the stream doesn't end now,
      // then we need to notify the reader on future changes.
      assert.strictEqual(asyncReadable._readableState.needReadable, true);
    }
  }, 3));
  
  process.nextTick(common.mustCall(() => {
    asyncReadable.push('foooo');
  }));
  process.nextTick(common.mustCall(() => {
    asyncReadable.push('bar');
  }));
  process.nextTick(common.mustCall(() => {
    asyncReadable.push(null);
  }));
  
  const flowing = new Readable({
    read: () => {}
  });
  
  // Notice this must be above the on('data') call.
  flowing.push('foooo');
  flowing.push('bar');
  flowing.push('quo');
  process.nextTick(common.mustCall(() => {
    flowing.push(null);
  }));
  
  // When the buffer already has enough data, and the stream is
  // in flowing mode, there is no need for the readable event.
  flowing.on('data', common.mustCall(function(data) {
    assert.strictEqual(flowing._readableState.needReadable, false);
  }, 3));
  
  const slowProducer = new Readable({
    read: () => {}
  });
  
  slowProducer.on('readable', common.mustCall(() => {
    if (slowProducer.read(8) === null) {
      // The buffer doesn't have enough data, and the stream is not need,
      // we need to notify the reader when data arrives.
      assert.strictEqual(slowProducer._readableState.needReadable, true);
    } else {
      assert.strictEqual(slowProducer._readableState.needReadable, false);
    }
  }, 4));
  
  process.nextTick(common.mustCall(() => {
    slowProducer.push('foo');
  }));
  process.nextTick(common.mustCall(() => {
    slowProducer.push('foo');
  }));
  process.nextTick(common.mustCall(() => {
    slowProducer.push('foo');
  }));
  process.nextTick(common.mustCall(() => {
    slowProducer.push(null);
  }));
  