old_contents: 'use strict'
  
  const shelljs = require('shelljs')
  const exec = require('./exec')
  const PLUGIN_PATH = require('./path').PLUGIN_PATH
  const checkRegistry = require('./check').registry
  const config = require('./config')
  const commands = require('./npm-commands.json')
  const pm = commands[require('./config').get('pm')] || commands.npm
  const logger = require('./logger')
  
  const npm = (options, registry) => {
    registry = registry || config.get('registry')
  
    if (registry) {
      options.push(checkRegistry(registry))
    }
  
    const pwd = shelljs.pwd().stdout
  
    shelljs.cd(PLUGIN_PATH)
    options = options.concat(['--save', '--silent', '--save-prefix=>='])
    exec(pm.name, options, {stdio: 'inherit'})
    shelljs.cd(pwd)
  }
  
  exports.install = (name, registry) => npm([pm.install].concat(name), registry)
  exports.update = (name, registry) => npm([pm.update].concat(name), registry)
  exports.uninstall = name => npm([pm.uninstall].concat(name))
  exports.list = () => npm(['list', '--depth=0'])
  
new_contents: 'use strict'
  
  const shelljs = require('shelljs')
  const exec = require('./exec')
  const PLUGIN_PATH = require('./path').PLUGIN_PATH
  const checkRegistry = require('./check').registry
  const config = require('./config')
  const commands = require('./npm-commands.json')
  const pm = commands[require('./config').get('pm')] || commands.npm
  
  const npm = (options, registry) => {
    registry = registry || config.get('registry')
  
    if (registry) {
      options.push(checkRegistry(registry))
    }
  
    const pwd = shelljs.pwd().stdout
  
    shelljs.cd(PLUGIN_PATH)
    options = options.concat(['--save', '--silent', '--save-prefix=>='])
    exec(pm.name, options, {stdio: 'inherit'})
    shelljs.cd(pwd)
  }
  
  exports.install = (name, registry) => npm([pm.install].concat(name), registry)
  exports.update = (name, registry) => npm([pm.update].concat(name), registry)
  exports.uninstall = name => npm([pm.uninstall].concat(name))
  exports.list = () => npm(['list', '--depth=0'])
  
subject: fix test