To install xvfb just follow these instructions.
sudo apt-get install xvfb
Which will install xvfb and any other packages on which it depends.
|Maintainer||Debian X Strike Force <email@example.com>|
|Description||Virtual Framebuffer 'fake' X server and no physical input devices. It emulates a dumb framebuffer using virtual memory. The primary use of this server was intended to be server testing, but other novel uses for it have been found, including testing clients against unusual depths and screen configurations, doing batch processing with Xvfb as a background rendering engine, load testing, as an aid to porting the X server to a new platform, and providing an unobtrusive way to run applications that don't really need an X server but insist on having one anyway.|