For an opinionated framework like Ruby on Rails, I expect it to come pre-bundled with a CoffeeScript based test framework and test runner. Here’s why:

• Teams don’t need to waste time deciding which one to use among the mess of Jasmine, Mocha, Expect, Sinon, Chai, Bower, Grunt, Teaspoon, Npm… you name it.

• It’d work better than what’s out there since the Rails team will focus on clean integration with Rails and will have a much larger user base to collect contribution from.

I’d prefer Jasmine to be the test framework and a runner similar to teaspoon that can run the specs both on the command line and on the browser, with asset pipelines enabled.

Rails made a huge promise to test automation by shipping with a nicely structured way to test the ruby code and doing the same for JS would make life better for so many people like me, I believe.