RuleTester prints \u000a instead of newline

[golopot]

Since eslint 6, rule tester prints newline in codes as \u000a. It is hard to read for plugin developers.

Code to repoduce

npx mocha index.js

// index.js

const {RuleTester} = require('eslint');

const someRule = {
  create() {
    return {};
  },
};

const ruleTester = new RuleTester();

ruleTester.run('some-rule', someRule, {
  valid: [],
  invalid: [
    {
      code: `
        var a;
        var b;
      `,
      errors: [{message: 'foooooooooooo'}],
    },
  ],
});

Actual output

Note the lines with \u000a.

  0 passing (46ms)
  1 failing

  1) some-rule
       invalid
         \u000a        var a;\u000a        var b;\u000a      :

      AssertionError [ERR_ASSERTION]: Should have 1 error but had 0: []
      + expected - actual

      -0
      +1

Expected ouput

This is the behavior with npm i eslint@5.

  1) some-rule
       invalid
         
        var a;
        var b;
      :

      AssertionError [ERR_ASSERTION]: Should have 1 error but had 0: []
      + expected - actual

      -0
      +1

[zamboney]

I would like it to be my first issue

[platinumazure]

Hi @golopot, thanks for the issue.

Based on your description, this does sound like a bug. Hopefully a team member can reproduce this bug soon so we can mark the issue as accepted. (I'm on vacation without access to my PC, so I can't test this myself right now.)

[ulrichb]

Same here:

(BTW: Running on Windows.)

[golopot]

An example in ci https://travis-ci.org/yannickcr/eslint-plugin-react/jobs/573750631

[platinumazure]

I'll mark as accepted based on the CI example. Thanks!