after.js VS Cucumber.js

Documentation

I did see this github link https://github.com/jaredpalmer/after.js/issues/49, however I am not using React native.

Within the React ecosystem there are other ways to achieve the same goal, either with After.js, Razzle or React-SSR.

After.js

What you're describing is most commonly known as acceptance testing, or behavior-driven tests. There's an excellent framework for this called Cucumber. They have gems for both plain Ruby and Rails.

It is a known fact that before any developer pushes the code (either to the development environment or Staging environment before migrating to the Production environment), he would be performing unit testing on the code changes that he has made. For unit testing, developers have a variety of unit-testing frameworks to choose from. JUnit and Jasmine are the most popular unit-testing frameworks. Other types of tests performed at a module/package level are functional tests and visual regression tests. Cucumber is a popular choice for Behavior-Driven Development (BDD) or functional testing, and a visual screenshot comparison tool named Wraith is preferred for performing visual regression testing.

Some BDD frameworks such as JBehave, RSpec, Mocha, Jasmine, Cucumber, among others, embrace the use of this template. Spek is not an exception to this rule. The main difference is that it doesn’t force you to use a concrete assertion framework or additional behavioral files (e.g Cucumber or JBehave).

There are a lot of more or less good testing frameworks in the wild. Some of existing testing frameworks doing their job very well and are de facto a standard, like a "cucumber" for BDD testing.

Just to add, anyone who is curious to learn more about BDD I would recommend checking out the Javascript flavor of Cucumber. It's cool stuff and immensely useful! https://github.com/cucumber/cucumber-js

And pretty deep into that rabbit hole you get Cucumber and the Gherkin language (https://cucumber.io/); project managers write "natural English" unit tests, but to get them to work, the developers write essentially a chatbot interpreter to process the files and run them.

Cucumber is an automation tool based on the BDD framework, using which you can write automated acceptance tests for web applications in the Gherkin language.

Many testing frameworks use Domain Specific Languages (DSLs) to define tests in plain English. Perhaps the most notable example is Gherkin, the language used by the Cucumber testing framework: