Jest Style Matchers

A small set of Jest matchers used for doing style-based linting, gathered here for my own uses. This is almost pure proof-of-concept, but feedback and improvements are welcome.

These matchers make use of htmllint, stylelint, and eslint for performing actual linting; see the associated docs and guides for more configuration options.

async toHaveNoHtmlLintErrorsAsync(filepath, config)

Checks whether the specified file path contains any errors. This is an asynchronous matcher. Takes in the path to a single .html file, as well as an object of htmllint options to use.

Usage:

//example lint options (none required)
const lintOpts = {
  'doctype-first':true,
  'indent-width':false, //don't need to beautify
  'class-style':'none', //I like dashes in classnames
  'img-req-alt':true, //for this test; captured later
}

//check the file
await expect('path/to/index.html').toHaveNoHtmlLintErrorsAsync(lintOpts);

async toHaveNoCssLintErrorsAsync(files, config)

Checks whether the specified file path contains any HTML linting errors. This is an asynchronous matcher. Works on a glob of CSS files to lint (per stylelint), and takes in an optional object of stylelint options to use (which are merged into the config option).

Usage:

//example config of custom rules
const config = {
  rules:{
    "declaration-colon-space-after": "always",
  }
}

//check the files
await expect('path/to/css/file.css').toHaveNoCssLintErrorsAsync(config);

toHaveNoEsLintErrors(sourcesList, options)

Checks whether the specified files contain any JavaScript linting errors. Works on an array glob of file sources (which is passed into into executeOnFiles()), and takes in an additional eslint config object (which has been lightly tested).

Usage:

//check the files
expect(['path/to/js/file.js']).toHaveNoEsLintErrors();