bundle.generate(...) now returns a Promise instead of a { code, map } object

[yandeqiang]

rollup version: 0.45.2

config:

preprocessors: {
      '__test__/index.js': ['rollup']
    },
    rollupPreprocessor: {
      plugins: [
        postcss({
          plugins: [
            cssnext()
          ],
          extensions: ['.css']
        }),
        babel({
          presets: ['es2015-rollup', 'stage-0'],
          plugins: [
            'transform-decorators-legacy',
            'transform-runtime'
          ],
          exclude: 'node_modules/**',
          runtimeHelpers: true,
          babelrc: false
        }),
        resolve(),
        commonjs()
      ],
      format: 'iife',
      sourceMap: 'inline'
    },

terminal console.log: bundle.generate(...) now returns a Promise instead of a { code, map } object

resolve: rollup issues