happo-plugin-gatsby

A happo.io plugin making it easy to add screenshot testing for Gatsby projects.

Usage

Add the following to your .happo.js configuration file:

// .happo.js
const happoPluginGatsby = require('happo-plugin-gatsby');

module.exports = {
  // ...
  plugins: [
    happoPluginGatsby({
      // options go here
    }),
  ],

  type: 'plain',
}

The Gatsby plugin for Happo takes screenshots on pre-built Gatsby pages. Therefore, before you run happo run you need to run a Gatsby build. Use the INSTALL_CMD environment variable to tell Happo to build before screenshooting. This could look something like this (using Travis CI as an example):

# .travis.yml
script:
- INSTALL_CMD="yarn build" yarn happo-ci

Options

pageFilter

By default, all Gatsby pages are included in the test suite. By providing a filter function, you can exclude certain pages. Here's an example excluding all "blog" pages:

happoPluginGatsby({
  pageFilter: (pathToFile) => {
    if (/\/blog/.test(pathToFile)) {
      // exclude blog pages
      return false;
    }
    return true;
  },
});

publicFolder

Use this option to override where Happo looks for pre-built Gatsby pages. The default is path.resolve(process.cwd(), 'public'). Make sure to use an absolute file path here.

const path = require('path');

happoPluginGatsby({
  publicFolder: path.resolve(__dirname, 'custom-build'),
});