Poltergeist - A PhantomJS driver for Capybara

Version: 0.6.0

Poltergeist is a driver for Capybara. It allows you to run your Capybara tests on a headless WebKit browser, provided by PhantomJS.

Installation

Add poltergeist to your Gemfile, and in your test setup add:

require 'capybara/poltergeist'
Capybara.javascript_driver = :poltergeist

If you were previously using the :rack_test driver, be aware that your app will now run in a separate thread and this can have consequences for transactional tests. See the Capybara README for more detail.

Installing PhantomJS

You need PhantomJS 1.6.0. There are no other dependencies (you don't need Qt, or Xvfb, etc.)

Note: Poltergeist 0.6 (the latest release) has a compatibility issue with PhantomJS 1.6 (the latest version, released 20th June). So use PhantomJS 1.5 for now. Poltergeist 0.7 will be release soon, with an update to support PhantomJS 1.6.

Mac

• With homebrew: brew install phantomjs
• Without homebrew: Download this

Linux

• Download the 32 bit or 64 bit binary.
• Extract it: sudo tar xvzf phantomjs-1.6.0-linux-*-dynamic.tar.gz -C /usr/local
• Link it: sudo ln -s /usr/local/phantomjs/bin/phantomjs /usr/local/bin/phantomjs

(Note that you cannot copy the /usr/local/phantomjs/bin/phantomjs binary elsewhere on its own as it dynamically links with other files in /usr/local/phantomjs/lib.)

Manual compilation

Do this as a last resort if the binaries don't work for you. It will take quite a long time as it has to build WebKit.

• Download the source tarball
• Extract and cd in
• ./build.sh

Compatibility

Supported: MRI 1.8.7, MRI 1.9.2, MRI 1.9.3, JRuby 1.8, JRuby 1.9.

Not supported:

• Rubinius (due to some unknown socket related issues)
• Windows

Contributions are welcome in order to move 'unsupported' items into the 'supported' list.

Running on a CI

There are no special steps to take. You don't need Xvfb or any running X server at all.

Depending on your tests, one thing that you may need is some fonts. If you're getting errors on a CI that don't occur during development then try taking some screenshots - it may well be missing fonts throwing things off kilter. Your distro will have various font packages available to install.

Travis CI has PhantomJS 1.5.0 installed. You may like to use their chef cookbook on your own servers.

What's supported?

Poltergeist supports basically everything that is supported by the stock Selenium driver, including Javascript, drag-and-drop, etc.

There are some additional features:

Taking screenshots

You can grab screenshots of the page at any point by calling page.driver.render('/path/to/file.png') (this works the same way as the PhantomJS render feature, so you can specify other extensions like .pdf, .gif, etc.)

By default, only the viewport will be rendered (the part of the page that is in view). To render the entire page, use page.driver.render('/path/to/file.png', :full => true).

Resizing the window

Sometimes the window size is important to how things are rendered. Poltergeist sets the window size to 1024x768 by default, but you can set this yourself with page.driver.resize(width, height).

Remote debugging (experimental)

If you use the :inspector => true option (see below), remote debugging will be enabled.

When this option is enabled, you can insert page.driver.debug into your tests to pause the test and launch a browser which gives you the WebKit inspector to view your test run with.

Read more here

(This feature is considered experimental - it needs more polish and apparently will only work on Linux until the next PhantomJS release.)

Setting request headers

Additional HTTP request headers can be set like so:

page.driver.headers = {
  "Cookie" => "foo=bar",
  "Host"   => "foo.com"
}

They will be cleared between tests, so you do not have to do this manually.

Inspecting network traffic

You can inspect the network traffic (i.e. what resources have been loaded) on the current page by calling page.driver.network_traffic. This returns an array of request objects. A request object has a response_parts method containing data about the response chunks.

Customization

You can customize the way that Capybara sets up Poltegeist via the following code in your test setup:

Capybara.register_driver :poltergeist do |app|
  Capybara::Poltergeist::Driver.new(app, options)
end

options is a hash of options. The following options are supported:

• :phantomjs (String) - A custom path to the phantomjs executable
• :debug (Boolean) - When true, debug output is logged to STDERR
• :logger (Object responding to puts) - When present, debug output is written to this object
• :timeout (Numeric) - The number of seconds we'll wait for a response when communicating with PhantomJS. nil means wait forever. Default is 30.
• :inspector (Boolean, String) - See 'Remote Debugging', above.
• :js_errors (Boolean) - When false, Javascript errors do not get re-raised in Ruby.
• :window_size (Array) - The dimensions of the browser window in which to test, expressed as a 2-element array, e.g. [1024, 768]. Default: [1024, 768]

Bugs

Please file bug reports on Github and include example code to reproduce the problem wherever possible. (Tests are even better.) Please also provide the output with :debug turned on, and screenshots if you think it's relevant.

Hacking

Contributions are very welcome and I will happily give commit access to anyone who does a few good pull requests.

To get setup, run bundle install. You can run the full test suite with rspec spec/ or rake.

While PhantomJS is capable of compiling and running CoffeeScript code directly, I prefer to compile the code myself and distribute that (it makes debugging easier). Running rake autocompile will watch the .coffee files for changes, and compile them into lib/capybara/client/compiled.

Changes

0.7.0 (unreleased)

Features

• Added an option ":js_errors", allowing poltergeist to continue running after JS errors. (John Griffin & Tom Stuart) [Issue #62] [Issue #69]
• Added an option ":window_size", allowing users to specify dimensions to which the browser window will be resized. (Tom Stuart) [Issue #53]
• Capybara 1.0 is no longer supported. Capybara ~> 1.1 is required.
• Added ability to set arbitrary http request headers
• Inspect network traffic on the page via page.driver.network_traffic (Doug McInnes) [Issue #77]

Bug fixes

• Fix issue with ClickFailed exception happening with a negative co-ordinate (which should be impossible). (Jon Leighton, Gabriel Sobrinho, Tom Stuart) [Issue #60]
• Fix issue with undefined method map for "[]":String, which happened when dealing with pages that include JS rewriting Array.prototype.toJSON. (Tom Stuart) [Issue #63]

0.6.0

Features

• Updated to PhantomJS 1.5.0, giving us proper support for reporting Javascript exception backtraces.

0.5.0

Features

• Detect if clicking an element will fail. If the click will actually hit another element (because that element is in front of the one we want to click), the user will now see an exception explaining what happened and which element would actually be targeted by the click. This should aid debugging. [Issue #25]

• Click elements at their middle position rather than the top-left. This is presumed to be more likely to succeed because the top-left may be obscured by overlapping elements, negative margins, etc. [Issue #26]

• Add experimental support for using the remote WebKit web inspector. This will only work with PhantomJS 1.5, which is not yet released, so it won't be officially supported by Poltergeist until 1.5 is released. [Issue #31]

• Add page.driver.quit method. If you spawn additional Capybara sessions, you might want to use this to reap the child phantomjs process. [Issue #24]

• Errors produced by Javascript on the page will now generate an exception within Ruby. [Issue #27]

• JRuby support. [Issue #20]

Bug fixes

• Fix bug where we could end up interacting with an obsolete element. [Issue #30]

• Raise an suitable error if PhantomJS returns a non-zero exit status. Previously a version error would be raised, indicating that the PhantomJS version was too old when in fact it did not start at all. [Issue #23]

• Ensure the :timeout option is actually used. [Issue #36]

• Nodes need to know which page they are associated with. Before this, if Javascript caused a new page to load, existing node references would be wrong, but wouldn't raise an ObsoleteNode error. [Issue #39]

• In some circumstances, we could end up missing an inline element when attempting to click it. This is due to the use of getBoundingClientRect(). We're now using getClientRects() to address this.

0.4.0

• Element click position is now calculated using the native getBoundingClientRect() method, which will be faster and less buggy.

• Handle window.confirm(). Always returns true, which is the same as capybara-webkit. [Issue #10]

• Handle window.prompt(). Returns the default value, if present, or null.

• Fix bug with page Javascript page loading causing problems. [Issue #19]

0.3.0

• There was a bad bug to do with clicking elements in a page where the page is smaller than the window. The incorrect position would be calculated, and so the click would happen in the wrong place. This is fixed. [Issue #8]

• Poltergeist didn't work in conjunction with the Thin web server, because that server uses Event Machine, and Poltergeist was assuming that it was the only thing in the process using EventMachine.

  To solve this, EventMachine usage has been completely removed, which has the welcome side-effect of being more efficient because we no longer have the overhead of running a mostly-idle event loop.

  [Issue #6]

• Added the :timeout option to configure the timeout when talking to PhantomJS.

0.2.0

• First version considered 'ready', hopefully fewer problems.

0.1.0

• First version, various problems.

License

Copyright (c) 2011 Jonathan Leighton

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.