code: function rerequire (module) {
    if (module[0] === '.') {
      module = Path.join(Path.dirname(getCaller()), module)
    }
  
    var oldkeys = Object.keys(require.cache)
    var result = require(module)
    var newkeys = Object.keys(require.cache)
    newkeys.forEach(function (newkey) {
      if (!~oldkeys.indexOf(newkey)) {
        delete require.cache[newkey]
      }
    })
    return result
  }
docs: Requires a module via `require()`, but invalidates the cache so it may be
  called again in the future. Useful for `mocha --watch`.
  
  var rerequire = require('mocha-jsdom').rerequire
  var $ = rerequire('jquery')