teampoltergeist--poltergeist/README.md

# Poltergeist - A PhantomJS driver for Capybara #

Version: 0.4.0

[![Build Status](https://secure.travis-ci.org/jonleighton/poltergeist.png)](http://travis-ci.org/jonleighton/poltergeist)
[![Dependency Status](https://gemnasium.com/jonleighton/poltergeist.png)](https://gemnasium.com/jonleighton/poltergeist)

Poltergeist is a driver for [Capybara](https://github.com/jnicklas/capybara). It allows you to
run your Capybara tests on a headless [WebKit](http://webkit.org) browser,
provided by [PhantomJS](http://www.phantomjs.org/).

## Installation ##

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

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

## Important note about Rack versions < 1.3.0 ##

Prior to version 1.3.0, the Rack handlers for Mongrel and Thin wrap your
app in the `Rack::Chunked` middleware so that it uses
`Transfer-Encoding: chunked`
([commit](https://github.com/rack/rack/commit/50cdd0bf000a9ffb3eb3760fda2ff3e1ad18f3a7)).
This has been observed to cause problems,
probably due to race conditions in Qt's HTTP handling code, so you are
recommended to avoid this by specifying your own server setup for
Capybara:

``` ruby
Capybara.server do |app, port|
  require 'rack/handler/thin'
  Thin::Logging.silent = true
  Thin::Server.new('0.0.0.0', port, app).start
end
```

If you're using Rails 3.0, this affects you. If you're using Rails 3.1+,
this doesn't affect you.

## Installing PhantomJS ##

You need PhantomJS 1.4.1+, built against Qt 4.8, on your system.

### Pre-built binaries ##

There are [pre-built
binaries](http://code.google.com/p/phantomjs/downloads/list) of
PhantomJS for Linux, Mac and Windows. This is the easiest and best way
to install it. The binaries including a patched version of Qt 4.8 so you
don't need to install that separately.

Note that if you have a 'dynamic' package, it's important to maintain
the relationship between `bin/phantomjs` and `lib/`. This is because the
`bin/phantomjs` binary looks in `../lib/` for its library files. So the
best thing to do is to link (rather than copy) it into your `PATH`:

    ln -s /path/to/phantomjs/bin/phantomjs /usr/local/bin/phantomjs

### Compiling PhantomJS ###

If you're having trouble with a pre-built binary package, you can
compile PhantomJS yourself. PhantomJS must be built against Qt 4.8, and
some patches must be applied, so note that you cannot build it against
your system install of Qt.

[Download the tarball](http://code.google.com/p/phantomjs/downloads/detail?name=phantomjs-1.4.1-source.tar.gz&can=2&q=)
and run either `deploy/build-linux.sh --qt-4.8` or `cd deploy; ./build-mac.sh`.
The script will
download Qt, apply some patches, build it, and then build PhantomJS
against the patched build of Qt. It takes quite a while, around 30
minutes on a modern computer with two hyperthreaded cores. Afterwards,
you should copy (or link) the `bin/phantomjs` binary into your `PATH`.

## Running on a CI ##

Currently PhantomJS is not yet 'truly headless' (but that's planned for the future),
so to run it on a continuous integration
server you will need to install [Xvfb](http://en.wikipedia.org/wiki/Xvfb).

### On any generic server ###

Install PhantomJS and invoke your tests with `xvfb-run`, (e.g. `xvfb-run
rake`).

### Using [Travis CI](http://travis-ci.org/) ###

Travis CI has PhantomJS installed already! So all you need to do is add
the following to your `.travis.yml`:

``` yaml
before_script:
  - "export DISPLAY=:99.0"
  - "sh -e /etc/init.d/xvfb start"
```

## 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)`.

## Customization ##

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

``` ruby
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.

## 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.

## Differences from [capybara-webkit](https://github.com/thoughtbot/capybara-webkit) ##

Poltergeist is similar to capybara-webkit, but here are the key
differences:

*   It's more hackable. Poltergeist is written in Ruby + CoffeeScript.
    We only have to worry about C++ when dealing with issues in
    PhantomJS itself. In contrast, the majority of capybara-webkit is
    written in C++.

*   We're able to tap into the PhantomJS community. When PhantomJS
    improves, Poltergeist improves. User's don't have to install Qt
    because self-contained PhantomJS binary packages are available.

## 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 ##

### 0.5.0 (unreleased) ###

#### 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]

#### 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]

### 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.