Packaging a ruby script as an Windows exe using OCRA

I recently wrote a watir-webdriver ruby script that I needed to be able distribute to others to run on Windows machines that don’t have ruby installed.

I came across the OCRA gem that allows you to easily generate a windows executable from a ruby script. This packages the ruby interpreter and all dependencies into an executable file.

It was quite straightforward to get it working, you simply install the gem on windows and run the ocra command with the name of your ruby script.

The only (minor) issues I had were:

  • if you wish to access external files from your executable (such as a config file) just add ‘$:.unshift File.dirname($0)‘ at the start of your ruby file
  • if you are using ruby logging, then for some reason you can’t call logger.close as it crashes OCRA, but you can just not close the logger which is fine
  • for some reason on Windows I needed to explicitly require ‘securerandom’ to use SecureRandom.uuid whereas it just worked on Mac OSX

Once I resolved these it quickly generated an executable which was runnable without any version of ruby installed. Neat.

A tale of three ruby automated testing APIs (redux)

Redux Note: I originally wrote a similar article to this before going on parental leave about six weeks ago. Whilst I didn’t intend to offend, it seemed that a few people took my article the wrong way. I understand that a lot of effort goes into creating a web testing API, but that doesn’t mean that everyone will agree with what you’ve made.

Sadly, an anonymous coward attacked myself and the company who I work (even though I don’t mention that company on this blog), so for the first time in this blog’s history, I have had to turn comment moderation on. I am sorry to the other genuine commenters whose comments have been lost in transition, and now have to wait for their new comments to be approved.

Since then I have received numerous emails asking where my article went, and commenting that people found it interesting and worthwhile. So I have decided to repost this article, hopefully with a little less contention this time around, making it clear, this is my opinion and experience: YMMV.


As a consultant I get to see and work on a lot of automated testing solutions using different automated web testing APIs. Lately I’ve been thinking about how these APIs are different and what makes them so.

My main interest is in ruby, and fortunately ruby has three solid examples of three different kinds of web testing APIs, two of which extend the lowest level API: selenium-webdriver.

I’ll (try to) explain here what I consider to be three kinds of automated web testing APIs and where I consider the sweet spot to be and and why.

A meaty example

As a carnivore, I thought I would explain my concept in terms I can relate to. If you’re a beef eater, there are many different kinds of beef that you can use to make some tasty food to eat. I’ll use three different kinds of beef for my example. The first (rawest) kind would involve getting a beef carcass and filleting it yourself to eventually make some edible food. The second kind of beef you could use is beef that is already in a slightly usable form, but you can then use yourself to make some edible food. For example, you can buy minced beef at a butcher, and then make your own hamburger patties, taco fillings etc from it. The final type of beef you could use is beef that has already been prepared so you can directly consume it, for example, sausages which can be cooked and consumed as is.

I consider these three examples of different kinds of beef to roughly correlate to automated web testing APIs, of which I also consider to be three kinds of.

The first is a Web Driver API, which is the rawest form of an API, its job is to drive a browser by issuing it commands. It provides a high level of user control, but like filleting a beef carcass it’s more ‘work’. An example in ruby of this API is the selenium-webdriver API, which controls the browser using the webdriver drivers.

The second kind of automated web testing API is the Browser API, which is a higher level API but still provides user control. This is the minced beef of APIs, as whilst it’s in a more usable form than a carcass, you still have a lot of control (and potential to what you can do with it). An example in ruby of this API is the watir-webdriver API, which uses the underlying selenium-webdriver carcass to control the browser.

The final kind of automated web testing API is the Web Form DSL (Domain Specific Language) which is a very high level API that provides users with specific methods to automate web forms and their elements. This is the beef sausages of APIs as sometimes you feel like eating something else besides sausages, but it’s difficult to make anything else edible but sausages from sausages. An example in ruby of this Web Form DSL is the Capybara DSL.

Visually, this looks something like this:

Show me the code™

So exactly what do these APIs look like?

I knew you’d ask, that’s why I came prepared.

Say I want to accomplish a fairly basic scenario on my example Google Doc form:

  • Start a browser
  • Navigate to the watir-webdriver-demo form
  • Check whether text field with id ‘entry_0’ exists (this should exist)
  • Check whether text field with id ‘entry_99’ exists (this shouldn’t exist)
  • Set a text field with id ‘entry_0’ to ‘1’
  • Set a text field with id ‘entry_0’ to ‘2’
  • Select ‘Ruby’ from select list with id ‘entry_1’
  • Click the Submit button

This is how I would do it in the three different APIs:

# * Start browser
# * Navigate to watir-webdriver-demo form
# * Check whether text field with id 'entry_0' exists
# * Check whether text field with id 'entry_99' exists
# * Set text field with id 'entry_0' to '1'
# * Set text field with id 'entry_0' to '2'
# * Select 'Ruby' from select list with id 'entry_1'
# * Click the Submit button

require 'bench'

benchmark 'selenium-webdriver' do
  require 'selenium-webdriver'

  driver = Selenium::WebDriver.for :firefox ''
    driver.find_element(:id, 'entry_0')
  rescue Selenium::WebDriver::Error::NoSuchElementError
    # doesn't exist
    driver.find_element(:id, 'entry_99').displayed?
  rescue Selenium::WebDriver::Error::NoSuchElementError
    # doesn't exist
  driver.find_element(:id, 'entry_0').clear
  driver.find_element(:id, 'entry_0').send_keys '1'
  driver.find_element(:id, 'entry_0').clear
  driver.find_element(:id, 'entry_0').send_keys '2'
  driver.find_element(:id, 'entry_1').find_element(:tag_name => 'option', :value => 'Ruby').click
  driver.find_element(:name, 'submit').click

benchmark 'watir-webdriver' do
  require 'watir-webdriver'
  b = Watir::Browser.start '', :firefox
  b.text_field(:id => 'entry_0').exists?
  b.text_field(:id => 'entry_99').exists?
  b.text_field(:id => 'entry_0').set '1'
  b.text_field(:id => 'entry_0').set '2'
  b.select_list(:id => 'entry_1').select 'Ruby'
  b.button(:name => 'submit').click

benchmark 'capybara' do
  require 'capybara'
  session =
  session.has_field?('entry_0') # => true
  session.has_no_field?('entry_99') # => true
  session.fill_in('entry_0', :with => '1')
  session.fill_in('entry_0', :with => '2')'Ruby', :from => 'entry_1')
  session.click_button 'Submit'

run 10

This is how long they took for me to run:

                        user     system      total        real
selenium-webdriver  1.810000   0.840000  22.130000 ( 73.123340)
watir-webdriver     1.940000   0.870000  24.380000 ( 79.388494)
capybara            1.950000   0.890000  24.080000 ( 79.920051)

Note: Capybara doesn’t always require a ‘session’, it’s only for non ruby rack applications, but since my example (Google) is not a rack application, as are most of the applications I test, my example must use the session.

When using ruby, why Watir-WebDriver is my sweet spot

I personally find Watir-WebDriver to be the most elegant solution, as the API is high enough for me to be highly readable/usable, but low enough to be powerful and for me to feel like I’m in control.

For example, being able to select an element by a explicit identifier (name, class name, id, anything) is a huge deal to me. I personally don’t like relying on the API to determine which selector to use: for example Capybara only supports name, id and label, but you can’t tell fill_in which specific one to choose: it appears to try each selector one by one until it finds it.

I have found that Watir-WebDriver also also provides lots of flexibility/neatness. For example: it’s the only API shown here that allows URLs to not have a ‘http://’ prefix (how many people do you know who type in http:// into a browser?).

In my opinion, the high level APIs like Capybara don’t provide enough control (for example – being able to specify the explicit selector), but the low level APIs like webdriver don’t provide enough functionality. This is evident when I am using a language other than ruby (like C#) when I find myself writing a large number of web element extension methods because webdriver doesn’t provide any of them. A .set method is a classic example, even Simon Stewart writes a clearAndType method in his examples even though he wrote webdriver which sadly misses it (you must call .clear, and .send_keys).

My biggest concern about high level field APIs

But my biggest issue with the high level APIs is that I’ve frequently seen them used to write test scripts that are step by step interactions with a web form. Instead of thinking of a business application as that, people see it as a series of forms that you ‘fill in’. This means people create scenarios like Aslak Hellesøy included in his recent post about cucumber web steps (which uses Capybara) and the problems it has created.

Scenario: Successful login
  Given a user "Aslak" with password "xyz"
  And I am on the login page
  And I fill in "User name" with "Aslak"
  And I fill in "Password" with "xyz"
  When I press "Log in"
  Then I should see "Welcome, Aslak"

I’m not saying it’s not possible to end up with something as ugly as above using other APIs, but I am saying the web form DSL style naturally relates to this: as the APIs look so similar to this style because that’s what the DSL was designed for: filling in forms. I’ve seen people frequently write generic, reusable cucumber steps to match the web form DSL like:

When /^I fill in "(.+)" with "(.+)"$/ do |value, field|
  fill_in field, :with => value

But this means you end up with less readable, less maintainable test scripts rather than business readable executable specifications.


Ultimately what I am looking for in an automated web testing API is simplicity and full control. I personally find browser APIs like Watir-WebDriver and Watir give me this, and this is why I love them so. Your mileage may vary, you may like different styles of APIs better, but I’ve seen other APIs so badly abused by people not even thinking about it, so it makes sense to think about what you’re trying to achieve and whether what you’re doing is the right way.

WatirMelon Spinach

Hello Spinach!

“Spinach is a new awesome BDD framework that features encapsulation and modularity of your step definitions.”

Seems like a good idea, so I thought I’d give it a try, and convert my existing simple Watirmelon Cucumber tests to use Spinach instead (link to my source code). It was very easy to do, here’s some observations:

  • It’s easy to get existing Cukes running using Spinach, but I imagine if you were starting out using Spinach you’d design things a lot differently
  • Steps belong in their own class, but you can include mixins to reuse steps – the ruby way
  • Steps are in a steps directory under features – shorter than step_definitions
  • Goodbye regular expressions in step definitions, which is a bit of a shame, as you can no longer capture values from the step name
  • As you can’t have regular expressions in step names, I find myself repeating steps that are similar but slightly different, this means my example steps have gone from 41 to 57 lines of code
  • Scenario Outlines aren’t supported at the moment, but I have raised this as a feature request
  • Hooks are dramatically improved, so I found them very easy to use and understand
  • There is no cucumber world, so you do a normal include instead, and env.rb is still supported
  • It displays really cool ticks on the command line when you’re running your spins

Well done to Codegram for releasing Spinach. If anything, it creates some great innovations that I imagine may find their way into Cucumber in the future.

Disabling native events when using Firefox with WebDriver

Imagine this, you’ve got a whole suite of regression tests (thousands of steps) written in Watir-WebDriver that you run on a corporate Windows XP SOE using Firefox.

The tests have been run numerous times and are running perfectly without any intermittent failures.

A new version of selenium-webdriver is released with promised bug fixes and stability improvements, so you update your selenium-webdriver gem to 2.6.0 and re-run your test suite.

Red light: half of the tests fail. The suite takes longer than ever to run. Oh my.

After some investigation, Jari Bakken points out that it’s Firefox native events related. This causes text field sets to take a long time if they include capital letters, and locating elements seems to often intermittently fail.

I add a config option to disable native events to my Firefox profile, and my tests run perfectly again. Phew!

So, if you’re using Windows and Firefox and come across any of these problems, include this code to disable native events when you start your browser.

profile =
profile.native_events = false WEB_DRIVER, :profile => profile

Running Watir-WebDriver tests on Travis CI: a distributed build system

I recently came across Travis CI, a distributed build system that has close links to Github. I’ve seen quite a few projects use it as a CI system, but none that run headless browser tests.

Leveraging off the work I had done recently setting up my own Jenkins server in the cloud to run headless Watir-WebDriver tests, I thought I would have a go at running my WatirMelonCucumber and EtsyWatirWebDriver headless browser tests using Travis CI.

What I didn’t realize is how easy it’d be. The only things I had to do was make sure my Gemfile included rake, and also make sure there was some file existance checking happening for some log files, and it pretty much ran straight away. Wow!

Caveat Emptor

This is pretty new territory, so there’s a few things to watch out for:

  • Every now and, Travis complains about not having Firefox installed. I am not sure why this happens, maybe something to do with the different agents in use;
  • The locale of the build agents seems to be German, so when running my Google tests, the page content is in German, so it fails because it can’t find my expected (English) results; and
  • I can’t seem to capture my test results html file nor screenshot pngs, so it’s a red/green only affair at the moment.

But still, neat distributed free headless CI!

Capturing screenshots in Watir-Webdriver & Cucumber

Update: 29 August – Thanks to Rob Hunter for the screenshot embed trick

When you’re running a suite of automated tests and one fails, I find it handy to capture a screenshot of the browser so it’s easier to investigate. Fortunately this is easier than ever before with Watir-Webdriver and it’s inbuilt save_screenshot method.

If you’re using Cucumber, you’ll be looking for something like this:

After do |scenario|
  if scenario.failed?
    Dir::mkdir('screenshots') if not'screenshots')
    screenshot = "./screenshots/FAILED_#{' ','_').gsub(/[^0-9A-Za-z_]/, '')}.png"
    embed screenshot, 'image/png'

The neatest thing about this method is that it captures the entire browser page, not just what is displayed without scrolling (see a screenshot of my blog below).

I hope you find this handy, I think it’s awesome.

Configuring Chrome settings when running Watir-Webdriver

I recently found the need to ignore certificate errors when running Watir-Webdriver tests in Google Chrome. The way to do this is slightly different from doing it in Firefox. Unlike Firefox where you create capabilities and profiles, in Google Chrome you pass arguments to Chrome to enable/disable certain browser features.

For example: to ignore certificate errors, disable pop-ups, disable translate and specify a proxy you do:

b = :chrome, :switches => %w[--ignore-certificate-errors --disable-popup-blocking --disable-translate]

NB: The %W[] converts a long string (separated by spaces) into an array of strings.

The full list of these options is available here. Thanks again to Jari Bakken for pointing me in the right direction.