Nowadays software development, and particularly web development, has become a more complex task than how it used to be a decade ago. This is easily noticeable if we include into the picture the current state of internet technology , its uses, the many browser flavours and the amount of devices today’s web applications must support.
Selenium (http://www.seleniumhq.org/): A suite of tools to automate web browsers across many platforms; its currently being used as a core component on many other Automation tools (like Sauce Labs).
Sauce Labs (https://saucelabs.com/): Suite for automated testing in the cloud for CI. It supports automated cross-browser testing with Selenium testing, automated mobile testing for iOS and Android and manual testing with over 450 browser flavours and OS platforms.
Travis CI (https://travis-ci.com/): It is an open-source hosted, distributed continuous integration service used to build and test projects hosted at GitHub.
I highly suggest you to take a look at these tools as they are the ones defining the shape of how next-gen testing will been done.