See the Leadfoot Command object API.
"Leadfoot can be installed and used as a stand-alone WebDriver library from npm by running npm install leadfoot. However, we recommend using Leadfoot through the Intern testing framework, which provides you with all of the tools you need to write robust unit and functional tests."
Ranked in these QuestionsQuestion Ranking
Pro Extensive, clear documentation
The documentation starts by describing what Intern is, what it's good for, who it's good for, its terminology, and continues with a tutorial.
Pro Used by big players
Intern is used by big companies such as IBM, Intuit and Mozilla.
Pro JS Foundation project
Intern (and Leadfoot) is a JS Foundation project. The JS Foundation is sponsored by IBM, Samsung, and other industry leaders.
Pro Comparisons available with Jasmine, Mocha, Karma, QUnit, Nightwatch, BusterJS
A project that compares itself with prior art has done its homework.
Pro Continuous Integration support
Pro Built-in support for source maps
The built-in support for source maps allows you to easily track issues to the original source files.
Pro Integrates with cloud hosted cross-browser testing services
Can integrate with cloud hosting services from BrowserStack, Sauce Labs and TestingBot.
Pro Always uses Promises
Since it always uses Promise objects every time an asynchronous operation needs to occur, the test system pauses until that Promise object is resolved, or until a timeout occurs. Suite, test and reporter functions can return a Promise.
Con Intern has no Cucumber support yet
Leadfoot can be used standalone though.
Con May be overkill for small apps
Intern is a complete testing framework that's designed to work well for enterprise applications. For small projects, the complexity of Intern can be unnecessary.