What is a Helper?

Helpers is a core concept of CodeceptJS. A Helper is a wrapper around a driver for talking to browsers, providing unified interface around them.

So we have a Puppeteer helper which talks to the Puppeteer driver, which talks to a Chrome browser.

The Nightmare helper talks to the Nightmare driver, which talks to an Electron 'browser'.

The Webdriver helper which talks the webdriver protocol to the Webdriverio driver, which talks to a Selenium server, which talks to a Firefox, Edge, or Chrome browser.

All these helpers implement (nearly) the same API.

• The Puppeteer helper implements amOnPage(url) to navigate to a URL.
• The Nightmare helper and the Webdriver helper also implement the amOnPage(url) function.

Methods of Helper class will be available in tests in I object. This abstracts test scenarios from the implementation and allows easy switching between backends.

Configuration

Helpers are defined and configured in the codecept.json file.

{ "helpers": {
    "Nightmare": {
      "url": "http://localhost",
      "show": false
} } }

You should only have one primary helper active at one time. Trying to configure both Puppeteer and Nightmare helpers at the same time won't work. There is a special multi mode for running the same tests in multiple browsers.

Custom Helpers

You can make your own helpers. These helpers are for adding your own custom functions, or for exposing a bit more of the underlying driver functionality without modifying CodeceptJS directly.

These helpers get added into the config file alongside the primary helper.

{ // ..
  "helpers": {
    "Nightmare": {
      "url": "http://localhost",
      "restart": false
    },
    "MyHelper": { }
  }
  // ..
}

Non-browser Helpers

The REST and Filesystem helpers are assistants. They do not pretend to be browsers, but add their own special APIs to the I object to make tests easier to write.

For example, the REST helper lets you write a test that can call a WebAPI to create a record.

These would also be used alongside the main helper:

{ // ..
  "helpers": {
    "Nightmare": {
      "url": "http://localhost",
      "restart": false
    },
    "MyHelper": { },
    "REST": {
        "endpoint": "http://localhost/api/"
    }
  }
  // ..
}