assert = require 'assert'
_      = require 'underscore'
Understream = require "#{__dirname}/../index"

charRange = (start, stop) ->
  if not stop? then stop = start; start = 0
  _.range(start, stop)
    .map (i) -> 'abcdefghijklmnopqrstuvwxyz'[i]

describe '_.batch(n)', ->
  it 'waits for n items, then outputs them in an array', (done) ->
    new Understream(charRange 20).batch(10).run (err, data) ->
      assert.ifError err
      assert.deepEqual data, [charRange(10), charRange(10, 20)]
      done()

  it 'outputs all items if n is greater than the number of items in the stream', (done) ->
    new Understream(charRange 5).batch(6).run (err, data) ->
      assert.ifError err
      assert.deepEqual data, [charRange(5)]
      done()

  it 'outputs any items it has if the input stream ends', (done) ->
    new Understream(charRange 13).batch(10).run (err, data) ->
      assert.ifError err
      assert.deepEqual data, [charRange(10), charRange(10, 13)]
      done()

  it 'outputs nothing for an empty stream', (done) ->
    new Understream([]).batch(10).run (err, data) ->
      assert.ifError err
      assert.deepEqual data, []
      done()