code: function(bucket) {
      var fs = require('fs');
      var path = require('path');
      var filePath = path.resolve('integ.buckets.json');
      var cache;
      if (fs.existsSync(filePath)) {
        try {
          cache = JSON.parse(fs.readFileSync(filePath));
          cache.buckets.push(bucket);
          fs.writeFileSync(filePath, JSON.stringify(cache));
        } catch (fileErr) {
          throw fileErr;
        }
      } else {
        cache = {};
        cache.buckets = [bucket];
        fs.writeFileSync(filePath, JSON.stringify(cache));
      }
    }
docs: Cache bucket names used for cleanup after all features have run.