unsupportedError = arg => {
        return {
          message: `Option ${arg} is unsupported by the mocha cli`,
          code: constants.UNSUPPORTED
        };
      }
/*.spec.js'});
        findupSync = sinon.stub();
        loadOptions = proxyLoadOptions({
          readFileSync,
          findConfig,
          loadConfig,
          findupSync
        });
        result = loadOptions(['--ignore', '*.test.js']);
      });

      it('should not split option values by comma', function () {
        expect(result, 'to have property', 'ignore', [
          '*.test.js',
          '{dirA,dirB}/*