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xvfbwrapper

Python wrapper for running a display inside X virtual framebuffer (Xvfb).

image


Info:


About Xvfb:

To run a program with a graphical display, you normally require X11 and a physical display attached. However, With Xvfb you can run headless inside a virtual dislpay. In the X Window System, X Virtual FrameBuffer (Xvfb or ") is an X11 server that performs all graphical operations in memory, not showing any screen output. This virtual server does not require the computer it is running on to even have a screen or any input device. Only a network layer is necessary.

Xvfb is often used for running acceptance tests on a headless server.


About xvfbwrapper:

xvfbwrapper is a small python wrapper for controlling Xvfb. It works nicely when Integrating with UI test suites in Python.


Install xvfbwrapper from PyPI:

pip install xvfbwrapper


System Requirements:

  • Xvfb (sudo apt-get install xvfb, or similar)
  • Python 2.7 or 3.2+ (tested on py27, py32, py33, py34, 3.5, pypy)

Examples

Basic Usage:

from xvfbwrapper import Xvfb

vdisplay = Xvfb()
vdisplay.start()

# launch stuff inside
# virtual display here.

vdisplay.stop()

Basic Usage, specifying display geometry and color depth:

from xvfbwrapper import Xvfb

vdisplay = Xvfb(width=1280, height=740, colordepth=16)
vdisplay.start()

# launch stuff inside
# virtual display here.

vdisplay.stop()

Usage as a Context Manager:

from xvfbwrapper import Xvfb

with Xvfb() as xvfb:
    # launch stuff inside virtual display here.
    # It starts/stops around this code block.

Testing Example: Headless Selenium WebDriver Tests:

import unittest

from selenium import webdriver
from xvfbwrapper import Xvfb


class TestPages(unittest.TestCase):

    def setUp(self):
        self.xvfb = Xvfb(width=1280, height=720)
        self.addCleanup(self.xvfb.stop)
        self.xvfb.start()
        self.browser = webdriver.Firefox()
        self.addCleanup(self.browser.quit)

    def testUbuntuHomepage(self):
        self.browser.get('http://www.ubuntu.com')
        self.assertIn('Ubuntu', self.browser.title)

    def testGoogleHomepage(self):
        self.browser.get('http://www.google.com')
        self.assertIn('Google', self.browser.title)


if __name__ == '__main__':
    unittest.main(verbosity=2)

The test class above uses selenium and xvfbwrapper to run each test case with Firefox inside a headless display.

  • virtual display is launched
  • Firefox launches inside virtual display (headless)
  • browser is not shown while tests are run
  • conditions are asserted in each test case
  • browser quits during cleanup
  • virtual display stops during cleanup

Look Ma', no browser!

(You can also take screenshots inside the virtual display for diagnosing test failures)