What is xvfb

It's a framebuffer that's in main memory instead of graphics memory, so you basically can't see it, but if your app environment needs a framebuffer for whatever reason and your hardware doesn't have graphics not uncommon in embedded apps then it can be useful.

It creates its own virtual framebuffer in userspace for use as an X display. It can be used with programs that need an X connection e. It doesn't need any kind of support from the kernel to do this - it uses a framebuffer, but really a framebuffer is just a fancy term for a chunk of memory used for a graphical screen. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Ask Question. Asked 8 years, 11 months ago. Active 4 years, 5 months ago. Viewed 6k times. Even though Wayland eliminates most of the design flaws of the Xorg it has its own issues. Wayland is not very stable yet, compared to Xorg.

Headless mode is a functionality that allows the execution of a full version of the latest Chrome browser while controlling it programmatically. Nightmare is a browser automation library. Under the hood, it uses Electron as a headless browser. Nightmare works well for automated user interface UI testing because it uses a simple application programming interface API , so writing tests is easy.

The localhost test will show how well everything performs, from the number of data packets received, sent, or lost, to how long the data transmission takes. For over 10 years, a display server protocol called Wayland has been in development. Its goal is to offer Linux-based systems a streamlined alternative to the widely adopted X Window System.

Ubuntu developers made Wayland the default session in Ubuntu By making clients responsible for all of their rendering, Wayland makes it possible for clients to be smarter about things like double-buffering.

There are other benefits outside of graphics. Starting in Chrome 59, you can now run headless Chrome. It brings all modern web platform features provided by Chrome to the command line.

Can we still take screenshots while running the code in headless browser mode? Easy Learning Idioms Dictionary. Selenium supports headless browser testing using HtmlUnitDriver.

HtmlUnitDriver is based on java framework HtmlUnit and is the one of the lightweight and fastest among all headless browser. You can read more about it in the man page here. Alternatively you can use the CI build number as your Xvfb display port. This way each display port is unique.

Each CI server is different, but you should have access to this value somehow. For example, this is made available through an environment variable in Jenkins. Hopefully this tip has helped you get your tests running smoothly on your CI Server. For more information on taking screenshots with Selenium, check out tip And to learn how to run a different browser locally e. The Problem If you want to run your tests headlessly on a Continuous Integration CI server you'll quickly realize that you can't with an out-of-the-box setup since there is no display output for the browser to launch in.

A Solution In order to run your tests using a browser that's loaded on your CI Server you will need to configure your tests to launch the browser virtually e. Let's take a look at an example.