text: var test = require('tape');
  var Volume = require('./');
  var Readable = require('stream').Readable;
  var Writable = require('stream').Writable;
  
  test('simple', function(t){
    emits(['foo', 'bar', 'baz'])
    .pipe(Volume(function(vol){
      t.equal(vol, 9);
    }))
    .pipe(drainAll())
    .on('finish', t.end.bind(t));
  });
  
  test('unicode', function(t){
    emits(['foo', 'bar', '\u00bd'])
    .pipe(Volume(function(vol){
      t.equal(vol, 8);
    }))
    .pipe(drainAll())
    .on('finish', t.end.bind(t));
  });
  
  function drainAll(){
    var dest = Writable();
    dest._write = function(chunk, enc, cb){
      cb();
    };
    return dest;
  }
  
  function emits(arr){
    var src = Readable();
    var i = 0;
    src._read = function(){
      this.push(arr[i++] || null);
    };
    return src;
  }
  