test

index.js

const ERROR = 2;

module.exports = {

  extends: [],

  parserOptions: {
    ecmaVersion: 6,
    sourceType: 'script',
  },

  plugins: [
    'no-loops',
  ],

  ecmaFeatures: {
    arrowFunctions: true,
  },

  rules: {
    'no-irregular-whitespace': ERROR,
    'no-tabs': ERROR,
    'no-loops/no-loops': ERROR,
  },
}

package.json

{
  "name": "my-repo",
  "version": "0.0.1",
  "description": "repo test",
  "main": "index.js",
  "dependencies": {
    "eslint-plugin-no-loops": "^0.3.0"
  },
  "devDependencies": {
    "eslint": "^3.3.1",
    "mocha": "^3.0.2"
  },
  "peerDependencies": {},
  "engines": {
    "node": ">= 4"
  },
  "scripts": {
    "test": "mocha test.js"
  }
}

test.js

/**
 * @fileoverview Tests for whitespace characters.
 */

const myConfig = require('./index.js');
const emptyRule = {
  meta: {
    docs: {
      description: 'Empty Rule to allow testing the entire config.',
      category: 'Stylistic Issues',
    },
    schema: [],
  },
  create(context) { return {}; },
};

const RuleTester = require('eslint').RuleTester;
RuleTester.setDefaultConfig(myConfig);
const ruleTester = new RuleTester();

ruleTester.run('whitespace-characters', emptyRule, {
  valid: [
    'var foo = 2;',
    'let foo = 2;',
    'const bar = 3;',
  ],

  invalid: [
    {
      code: '\t	let foo = 2;',
      errors: 1,

    },
  ],
});