code: function (coverage /*, testName */) {
          var store = this.store;
          Object.keys(coverage).forEach(function (key) {
              var fileCoverage = coverage[key];
              if (store.hasKey(key)) {
                  store.setObject(key, utils.mergeFileCoverage(fileCoverage, store.getObject(key)));
              } else {
                  store.setObject(key, fileCoverage);
              }
          });
      }
docs: adds a coverage object to the collector.
  
  @method add
  @param {Object} coverage the coverage object.
  @param {String} testName Optional. The name of the test used to produce the object.
  This is currently not used.