This module would be covvenient when you write test for your original stream. You don't need a file to provide a big data for your test.

How to use

var createGeneratorStream = require('../').create,
    count = 0,
    generator = createGeneratorStream(function() {
      // return buffer. and then return null when finished.
      return count < 3 ? new Buffer('hello world:' + (count++)) : null;
    }),
    fs = require('fs'),
    out = fs.createWriteStream('out.txt');

generator.setEncoding('utf8');
generator.pipe(out);

out.on('close', function() {
  expect(fs.readFileSync('out.txt', 'utf8')).to.equal('hello world:0hello world:1hello world:2');
  done();
});

Generator function

You can use following function types.

function() {return Buffer;}

• synchronous generator
• just return Buffer
• return null when finished

function(done) {done(error, Buffer);}

• asynchronous generator
• call done(error, buffer) when ready buffer. You will call done(null, buffer) in usual cases
• call done(null, null) when finished

Run tests

npm install -d
npm test