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Updated: How to change the hostname in Cucumber features

Updated example step for Capybara > 2.14. New usage:

page.config.stub app_host: "http://#{host}"

Upgrading a Rails app to Cucumber 3

Upgrade gems

You need to update a lof gems. Make sure you don't have any version constraints in your Gemfile or your bundle update won't do anything!

Upgrade cucumber_priority:

bundle update cucumber_priority

Upgrade spreewald:

bundle update spreewald

Upgrade cucumber_factory:

bundle update cucumber_factory

Upgrade parallel_tests:

bundle update parallel_tests

Even on the latest version, parallel_tests will print some deprecation warnings due to using an older formatter A…

VNC browser disappears while typing

We often use the Then console step from spreewald in combination with geordi vnc from geordi to debug tests within a real browser. Sometimes when you type in the browser it suddenly disappears. You will only see a grey screen then.

This will always happen if you press the d key. Press the d key again and the browser will appear again.


How to stub class constants in RSpec

Hint: There's another card with this helper for Cucumber features.

Sometimes you feel like you need to stub some CONSTANT you have defined in an other class. Since actually constants are called constants because they're constant, there's no way to easily stub a constant.

Here are three solutions for you.

Easiest solution

Rethink! Do you really need CONSTANT = %w[foo bar] to be constant? In many cases, setting it as a…

Capybara: A step for finding images with filename and extension

This cucumber step is useful for testing an image (looking at the src of the image).

Then(/^I should see the image "([^"]*)"$/) do |filename_with_extension|
  expect(page).to have_css("img[src*='#{filename_with_extension}']")
Then I should see the image "placeholder.png"

Outline: Read more about how to test a uploaded file here, e.g. file downloads.

Error during Rails 5 upgrade: Environment data not found in the schema

This error is raised because your old database does not have a configured environment yet, which Rails 5 enforces.

If this error occurs while migrating your parallel test databases, make sure to update the parallel_tests gem first: current versions fix this. If you're still using Cucumber < v3, the latest version of parallel_tests will be 2.18.0.

RubyMine: You can disable inspections you don't care about

When you find yourself constantly ignoring a RubyMine warning, you can simple disable that warning and de-clutter your editor. E.g. in my Cucumber scenarios RubyMine underlines 90% of all lines because it does not know about spreewald, making the file really hard to read.

You can disable any unwanted inspection by opening File / Settings / Editor / Inspections and searching for the warning text.

What you disable or keep is up to your personal preference. I personally disable at least the following…

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Spreewald 1.11.0 console step starts irb in execution context

You can now e.g. run steps within the irb console.


You want to debug why your fill in step is not working. Add the console step before this step.

When I select "Rejection" from "Decision"
Then console
Then I fill in "Comment" with "Some comment"

Run the test, open the vnc with geordi and try to reproduce the error step by step:

# This is new: You can now access step, page, with_scope and others.

irb> step('Then I fill in "Comment" with "Some comment"')
irb> fill_in("Comment", :with => "Some comment") …

Firefox: Focus-sensitive Selenium tests do not work reliably in parallel test execution

This is a problem when using Selenium with Firefox. We recommend using ChromeDriver for your Selenium tests.

Firefox will not trigger focus/blur events when its window is not focused. While this makes sense in standard usage, it breaks in parallel test execution.

Please do not rely on focus events in your tests. The linked card has an example of how to build passing tests that deal with focus/blur events.

How to control Chromedriver using curl

Here is how to use Chromedriver without libraries like selenium-webdriver. This can be useful for debugging.

The following example visits a web page and reads the a headline's text contents.

  1. Create a session:

    curl -XPOST http://localhost:9515/session -d '{"desiredCapabilities":{"browserName":"chrome"}}'

    You will get a JSON response containing lots of information about your Chrome session, including a sessionId. Use this to send any future commands to your chromedriver session.


Form letters with LibreOffice Writer

This is painful. Consider using Microsoft Office or switching careers. If you need to write < 20 letters consider doing it manually.

So you didn't listen and here it comes:

  1. Ignore the Mail Merge Wizard. It will crash or destroy your document.
  2. Export your addresses, recipient names, etc. as a .ods spreadsheet (.xls, .xlsx, .ods). Use any columns that work for you, but be consistent. I like to use one column for the address, one column for the salutation line.
  3. Import the spreadsheet as an address book source: *Tools => Add…

Why your Cucumber feature loses cookies when run under Selenium or capybara-webkit

When your Cucumber feature seems to forget cookies / sessions when you run it with Selenium or capybara-webkit, check if the test travels in time like here:

Given the date is 1981-10-20
When I sign in
Then I should see "Welcome!"

What happens here is that the Rails application serving pages runs in 1984, but the process running your Firefox or Webkit still lives today. This gap of 27+ years will expire most Cookies immediately.

If all you need is to freeze the time to a date, a workaround is to travel to the future instead.


Detect the current Rails environment from JavaScript or CSS

Detecting if a Javascript is running under Selenium WebDriver is super-painful. It's much easier to detect the current Rails environment instead.

You might be better of checking against the name of the current Rails environment. To do this, store the environment name in a data-environment of your <body>. E.g., in your application layout:

%body{'data-environment' => Rails.env}

Now you can say in a piece of Jav…


Grep through the DOM using the Capybara API

When your Cucumber feature needs to browse the page HTML, and you are not sure how to express your query as a clever CSS or XPath expression, there is another way: You can use all and find to grep through the DOM and then perform your search in plain Ruby.

Here is an example for this technique:

Then /^I should see an image with the filename...

Nested Spreewald patiently blocks are now patient

In Spreewald 1.10.4+, nested patiently blocks are now patient.

Here is an example:

patiently do
  patiently do

On spreewald 1.11.2+ the inner block will wait for the full configured wait time (by default 5 seconds). The outer patiently block would now be out of time, but it will always be retried at least a second time.

In versions 1.10.4 - 1.11.1, inner blocks would keep giving the outer block additional time to finish, which solves the same issues, but as a downside can cause the wh…

Cucumber: How to avoid VCR errors for unused requests in pending tests

When you have a pending Cucumber step (or feature) that also uses an existing VCR cassette, your pending test may fail at the very end with an error like this:

There are unused HTTP interactions left in the cassette:
  - [get ...] => [200 ...]
  - [get ...] => [200 ...] (VCR::Errors::UnusedHTTPInteractionError)

The error happens because your VCR is configured to complain about cassettes that contain extra requests which your test did not use. This is often a good configuration.
If you do not want to change your whole test suite…


Check that an element is hidden via CSS with Spreewald

If you have content inside a page that is hidden by CSS, the following will work with Selenium, but not when using the Rack::Test driver:

Then I should not see "foobear"

This is because the Rack::Test driver does not know if an element is visible, and only looks at the DOM.

Spreewald offers steps to check that an element is hidden by CSS:

Then "foo" should be hidden # "should not be visible" in Spreewald < 1.2.3

You can also check that an element is visible:

Then "foo" shou...

chromedriver-helper gem in Gemfile might break you selenium tests (of other projects)

Summary: Don't add chromedriver-helper to the Gemfile

  • the executables might break your tests in projects where chromedriver-helper is not in the Gemfile
  • developers with different chrome versions will have problems using the same chromedriver-helper version


If you install the chromedriver-helper gem, but don't have it in you Gemfile, your selenium tests might fail with:

Selenium::WebDriver::Error::WebDriverError: unable to connect to chromedriver

The reason is that chromedriver-helper o…