Extending CodeceptJS

# Extending

CodeceptJS provides API to run custom code before and after the test and inject custom listeners into the event system.

# Plugins

Plugins allow to use CodeceptJS internal API to extend functionality. Use internal event dispatcher, container, output, promise recorder, to create your own reporters, test listeners, etc.

CodeceptJS includes built-in plugins which extend basic functionality and can be turned on and off on purpose. Taking them as examples (opens new window) you can develop your custom plugins.

A plugin is a basic JS module returning a function. Plugins can have individual configs which are passed into this function:

const defaultConfig = {
  someDefaultOption: true
}

module.exports = function(config) {
  config = Object.assign(defaultConfig, config);
  // do stuff
}

Plugin can register event listeners or hook into promise chain with recorder. See API reference (opens new window).

To enable your custom plugin in config add it to plugins section. Specify path to node module using require.

"plugins": {
  "myPlugin": {
    "require": "./path/to/my/module",
    "enabled": true
  }
}
  • require - specifies relative path to a plugin file. Path is relative to config file.
  • enabled - to enable this plugin.

If a plugin is disabled (enabled is not set or false) this plugin can be enabled from command line:

npx codeceptjs run --plugin myPlugin

Several plugins can be enabled as well:

npx codeceptjs run --plugin myPlugin,allure

# Example: Execute code for a specific group of tests

If you need to execute some code before a group of tests, you can mark these tests with a same tag. Then to listen for tests where this tag is included (see test object api).

Let's say we need to populate database for a group of tests.

// populate database for slow tests
const event = require('codeceptjs').event;

module.exports = function() {

  event.dispatcher.on(event.test.before, function (test) {

    if (test.tags.indexOf('@populate') >= 0) {
      recorder.add('populate database', async () => {
        // populate database for this test
      })
    }
  });
}

# Example: Check URL before running a test

If you want to share bootstrap script or run multiple bootstraps, it's a good idea to wrap that script into a plugin. Plugin can also execute JS before tests but you need to use internal APIs to synchronize promises.

const { recorder } = require('codeceptjs');

module.exports = function(options) {

  event.dispatcher.on(event.all.before, function () {
    recorder.startUnlessRunning(); // start recording promises
    recorder.add('do some async stuff', async () => {
      // your code
    });
  });
}

# API

Use local CodeceptJS installation to get access to codeceptjs module

CodeceptJS provides an API which can be loaded via require('codeceptjs') when CodeceptJS is installed locally. These internal objects are available:

API reference (opens new window) is available on GitHub. Also please check the source code of corresponding modules.

# Event Listeners

CodeceptJS provides a module with event dispatcher and set of predefined events (opens new window).

It can be required from codeceptjs package if it is installed locally.

const event = require('codeceptjs').event;

module.exports = function() {

  event.dispatcher.on(event.test.before, function (test) {

    console.log('--- I am before test --');

  });
}

Available events:

  • event.test.before(test) - async when Before hooks from helpers and from test is executed

  • event.test.after(test) - async after each test

  • event.test.started(test) - sync at the very beginning of a test. Passes a current test object.

  • event.test.passed(test) - sync when test passed

  • event.test.failed(test, error) - sync when test failed

  • event.test.finished(test) - sync when test finished

  • event.suite.before(suite) - async before a suite

  • event.suite.after(suite) - async after a suite

  • event.step.before(step) - async when the step is scheduled for execution

  • event.step.after(step) - async after a step

  • event.step.started(step) - sync when step starts.

  • event.step.passed(step) - sync when step passed.

  • event.step.failed(step, err) - sync when step failed.

  • event.step.finished(step) - sync when step finishes.

  • event.step.comment(step) - sync fired for comments like I.say.

  • event.bddStep.before(bddStep) - async when the gherkin step is scheduled for execution

  • event.bddStep.after(bddStep) - async after a gherkin step

  • event.all.before - before running tests

  • event.all.after - after running tests

  • event.all.result - when results are printed

  • sync - means that event is fired in the moment of action happens.

  • async - means that event is fired when an actions is scheduled. Use recorder to schedule your actions.

For further reference look for currently available listeners (opens new window) using event system.

# Test Object

Test events provide a test object with following fields:

  • title title of a test
  • body test function as a string
  • opts additional test options like retries, and others
  • pending true if test is scheduled for execution and false if a test has finished
  • tags array of tags for this test
  • file path to a file with a test.
  • steps array of executed steps (available only in test.passed, test.failed, test.finished event)
  • skipInfo additional test options when test skipped
    • message string with reason for skip
    • description string with test body and others

# Step Object

Step events provide step objects with following fields:

  • name name of a step, like 'see', 'click', and others
  • actor current actor, in most cases it I
  • helper current helper instance used to execute this step
  • helperMethod corresponding helper method, in most cases is the same as name
  • status status of a step (passed or failed)
  • prefix if a step is executed inside within block contain within text, like: 'Within .js-signup-form'.
  • args passed arguments

# Recorder

To inject asynchronous functions in a test or before/after a test you can subscribe to corresponding event and register a function inside a recorder object. Recorder (opens new window) represents a global promises chain.

Provide a function description as a first parameter, function should return a promise:

const event = require('codeceptjs').event;
const recorder = require('codeceptjs').recorder;
module.exports = function() {

  event.dispatcher.on(event.test.before, function (test) {

    const request = require('request');

    recorder.add('create fixture data via API', function() {
      return new Promise((doneFn, errFn) => {
        request({
          baseUrl: 'http://api.site.com/',
          method: 'POST',
          url: '/users',
          json: { name: 'john', email: '[email protected]' }
        }), (err, httpResponse, body) => {
          if (err) return errFn(err);
          doneFn();
        }
      });
    }
  });
}

Whenever you execute tests with --verbose option you will see registered events and promises executed by a recorder.

# Output

Output module provides 4 verbosity levels. Depending on the mode you can have different information printed using corresponding functions.

  • default: prints basic information using output.print
  • steps: toggled by --steps option, prints step execution
  • debug: toggled by --debug option, prints steps, and debug information with output.debug
  • verbose: toggled by --verbose prints debug information and internal logs with output.log

It is recommended to avoid console.log and use output.* methods for printing.

const output = require('codeceptjs').output;

output.print('This is basic information');
output.debug('This is debug information');
output.log('This is verbose logging information');

# Container

CodeceptJS has a dependency injection container with Helpers and Support objects. They can be retrieved from the container:

let container = require('codeceptjs').container;

// get object with all helpers
let helpers = container.helpers();

// get helper by name
let WebDriver = container.helpers('WebDriver');

// get support objects
let support = container.support();

// get support object by name
let UserPage = container.support('UserPage');

// get all registered plugins
let plugins = container.plugins();

New objects can also be added to container in runtime:

let container = require('codeceptjs').container;

container.append({
  helpers: { // add helper
    MyHelper: new MyHelper({ config1: 'val1' });
  },
  support: { // add page object
    UserPage: require('./pages/user');
  }
})

Container also contains current Mocha instance:

let mocha = container.mocha();

# Config

CodeceptJS config can be accessed from require('codeceptjs').config.get():


let config = require('codeceptjs').config.get();

if (config.myKey == 'value') {
  // run hook
}

# Custom Runner

📺 Watch this (opens new window) material on YouTube

CodeceptJS can be imported and used in custom runners. To initialize Codecept you need to create Config and Container objects.

const { codecept: Codecept } = require('codeceptjs');

const config = { helpers: { WebDriver: { browser: 'chrome', url: 'http://localhost' } } };
const opts = { steps: true };

const codecept = new Codecept(config, options);
codecept.init(testRoot);

// run tests
try {
  await codecept.bootstrap();
  codecept.loadTests('*_test.js');
  await codecept.run(test);
} catch (err) {
  printError(err);
  process.exitCode = 1;
} finally {
  await codecept.teardown();
}


In this way Codecept runner class can be extended.

Last Updated: 9/30/2020, 3:49:15 PM