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Integrating Percy with your Nightwatch tests

Package Status

Visual regression testing for Nightwatch tests with Percy.



Make sure you have completed Setup of your CI service first. You can also test Percy in your local development environment.

Install @percy/nightwatch using npm:

npm install --save-dev @percy/nightwatch

Quick Setup

These are the minimal steps required to add visual testing to your existing Nightwatch tests:

  1. Add the path to the percySnapshot command to the custom_commands_path array in your Nightwatch configuration: const percy = require('@percy/nightwatch) and custom_commands_path: [ percy.path ].
  2. Call browser.percySnapshot() from your tests wherever you want to save a snapshot.
  3. Wrap your test run command in percy exec --, e.g. percy exec -- nightwatch.

Next, we will go through each of these steps in detail.


In order to start creating snapshots from your Nightwatch tests, you'll need to add the custom percySnapshot() command to your Nightwatch configuration.

To do that, add the path to your @percy/nightwatch installation to the custom_commands_path array in your Nightwatch configuration. @percy/nightwatch provides a path property that you can use for this.

In your Nightwatch configuration (typically nightwatch.conf.js or nightwatch.json):

const percy = require('@percy/nightwatch')

module.exports = {
  custom_commands_path: [ percy.path ],

You can now use browser.percySnapshot() to generate a snapshot:

'Loads the app': function(browser) {

Finally, wrap your test runner in the percy exec command. This will start a Percy agent to receive snapshots from your tests and upload them to your Percy dashboard. Your new test command becomes:

percy exec -- nightwatch

Note the double dash with spaces, --, between percy exec and your test run command.

That's it! Now, whenever CI runs, a snapshot of the app in that state will be uploaded to Percy for visual regression testing!

For an example showing how to add Percy snapshots to an existing Nightwatch test suite, see https://github.com/percy/example-percy-nightwatch/pull/3/files.


browser.percySnapshot(snapshotName, options)

snapshotName is a string that will be used as the snapshot name. It can be any string that makes sense to you to identify the page state. It should be unique and remain the same across builds. If not provided, Percy will use the name of the currently executing test. For more details on generating snapshot names, see Autogenerated snapshot names.

options is an optional hash that can include:

  • widths: An array of integers representing the browser widths at which you want to take snapshots.

  • minHeight: An integer specifying the minimum height of the resulting snapshot, in pixels. Defaults to 1024px.


browser is the Nightwatch browser instance that is passed into your tests.


browser.percySnapshot('Homepage test');
browser.percySnapshot('Homepage responsive test', { widths: [768, 992, 1200] });

Global Configuration

You can also configure Percy to use the same options over all snapshots. To see supported configuration including widths read our Configuration doc.


  1. Fork it ( https://github.com/percy/percy-nightwatch/fork )
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new pull request

Throw a ★ on it! 😄