eslint-config-x.js

module.exports = {
  parser: 'babel-eslint',
  plugins: ['babel', 'react'],
  envs: {
    es6: true,
    node: true
  },
  ecmaFeatures: {
    jsx: true
  },
  rules: {
    'react/jsx-uses-react': 2,
    'react/react-in-jsx-scope': 2
  }
}

fixture.js

/* @flow */
class Foo {
  render() : ReactElement {
    return <div></div>
  }
}

package.json

{
  "devDependencies": {
    "eslint": "^1.3.1"
  },
  "dependencies": {
    "babel-eslint": "^4.1.1",
    "eslint-plugin-babel": "^2.1.1",
    "eslint-plugin-react": "^3.3.1"
  }
}

test_config.js

var fs = require('fs');
var eslint = require('eslint');
var tempWrite = require('temp-write');
var test = require('ava');

test('node', function(t) {
  var conf = require('./eslint-config-x');
  var file = fs.readFileSync('./fixture.js', { encoding: 'utf-8'} );
  var linter = new eslint.CLIEngine({
    useEslintrc: false,
    configFile: tempWrite.sync(JSON.stringify(conf))
  });
  
  var errors = linter.executeOnText(file).results[0].messages;
})