This card shows basic techniques for fixing a flaky integration test suite that sometimes passes and sometimes fails. "Integration test" is a test script that remote-controls a web browser with tools like Selenium WebDriver.

Although the examples in this card use Cucumber and Selenium, the techniques are applicable to all languages and testing tools.

Why tests are flaky

Your tests probably look like this:

When I click on A
When I click on B
When I click on C
Then I should see effects of C

A test like this works fine most of t…

When you want to group rails models of a logical context, namespaces are your friend. However, if you have a lot of classes in the same namespace it might be tedious to specify the table name for each class seperately:

class Accounting::Invoice < ApplicationRecord
  self.table_name = 'accounting_invoices'
  ...
end

class Accounting::Payment < ApplicationRecord
  self.table_name = 'accounting_payments'
  ...
end

A replacement for the self.table_name-assignment is the table_name_prefix in the module definition:

```
module Accou…

Summary

• around(:suite) does not exist.
• around(:all) runs after before(:all) and before after(:all).
• around(:each) runs before before(:each) and after after(:each).

As this is not 100% obvious (and not yet documented) it is written down in this card. In RSpec 3 :each has the alias :example and :all the alias :context.

Example

```
RSpec.configure do |config|
config.before(:suite) { puts 'BEFORE :suite' }
config.after(:suite) { puts 'AFTER :suite' }
end

describe 'order of hook execution' do
around(:a…

Spreewald comes with a selector_for helper that matches an English term like the user's profile into a CSS selector. This is useful for steps that refer to a particular section of the page, like the following:

Then I should see "Bruce" within the user's profile
                                 ^^^^^^^^^^^^^^^^^^

If you're too lazy to manually translate English to a CSS selector by adding a line to features/env/selectors.rb, we already have an [auto-mapper to translate English into …

Selenium cannot reliably control a browser when its window is not in focus, or when you accidentally interact with the browser frame. This will result in flickering tests, which are "randomly" red and green. In fact, this behavior is not random at all and completely depends on whether or not the browser window had focus at the time.

This card will give you a better understanding of Selenium focus issues, and what you can do to get your test suite stable again.

Preventing accidental interaction with the Selenium window ——————–…

When using geordi for integration tests you might get the following error when trying to run geordi cucumber:

unable to obtain stable firefox connection in 60 seconds (127.0.0.1:7055) (Selenium::WebDriver::Error::WebDriverError)

This means, that the vnc window the tests is talking to has no proper firefox version running. To figure out the issue this might help you:

• Check if the .firefox-version (e.g. 24.0) is the same as ~/bin/firefoxes/24.0/firefox says in the browser
• Maybe [rest…

Webpack is the future. We're using it in our latest Rails applications.

For tests, we want to compile assets like for production.
For parallel tests, we want to avoid 8 workers compiling the same files at the same time.
When assets did not change, we do not want to spend time compiling them.

Here is our solution for all that.

Its concept should work for all test suites. For Cucumber integration tests, place the following into features/support/webpacker.rb.

```
module WebpackerTestSupport
module_function def compile_once
digest_fi…

I needed to make sure that an element is visible and not overshadowed by an element that has a higher z-index (like a modal overlay).

Here is the step I wanted:

Then the very important notice should not be overshadowed by another element

This is the step definition:

```
Then(/^(.*?) should not be overshadowed by another element$/) do |locator|
selector = selector_for(locator)
expect(page).to have_css(selector)
js = «-JS
var selector = #{selector.to_json};
var elementFromSelector = document.querySelector(selector)…

ChromeDriver clicking works by simulating a mouse click in the middle of the element's first client rect (or bounding client rect if it doesn't have a first client rect). (Clicking issues)

So if you are trying to click on an element, chromedriver tries to click at the position where it first finds that element.

This can lead to some problems and unexpected behavior like:

• Element is not clickable at point ... erros
• Another element which is now located at…

Middleman is a static page generator that brings many of the goodies that Rails developers are used to.

Out of the box, Middleman brings Haml, Sass, helpers etc. However, it can be configured to do even better. This card is a list of improvement hints for a Rails developer.

Gemfile

Remove tzinfo-data and wdm unless you're on Windows. Add these gems:

```
gem 'middleman-livereload'
gem 'middleman-sprockets' # Asset pipeline!

gem 'bootstrap-sass' # If you want to use Bootstrap

gem 'byebug'

gem 'capistrano'
gem 'capistrano-mid…

These steps are now part of Spreewald.

This note describes a Cucumber step that lets you write this:

Then I should see a table with the following rows:
  | Bruce Wayne       | Employee    | 1972 |
  | Harleen Quinzel   | HR          | 1982 |
  | Alfred Pennyworth | Engineering | 1943 |

If there are additional columns or rows in the table that are not explicitely expected, the step won't complain. It does however expect the rows to be ordered as stat…

When filling out forms in Selenium tests, Chrome shows the (usual) bubble, asking to store those credentials.

While the bubble does not interfere with tests, it is annoying when debugging tests. Here are two ways to disable it:

Option 1: prefs

You can set profile preferences to disable the password manager like so:

prefs = {
  'credentials_enable_service' => false,
  'profile.password_manager_enabled' => false
}

Capybara::Selenium::Driver.new(app, browser: :chrome, prefs: prefs)

Sadly, there are no command line s…

In a JavaScript console, type this:

> 9112347935156469760
9112347935156470000

Ooops.

This occurs because JavaScript uses double precision floats to store numbers.

So according to IEEE floating point definition only numbers between -(2^53 - 1) (-9007199254740991) and 2^53 - 1 (9007199254740991) can safely be represented in JavaScript.

Note that ECMAScript 6 will probably also offer [Number.MAX_SAFE_INTEGER](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference…

There seems to be a nasty bug in Chrome 56 when testing with Selenium and Capybara: Slashes are not written to input fields with fill_in. A workaround is to use javascript / jquery to change the contents of an input field.

Use the following code or add the attached file to your features/support/-directory to overwrite fill_in.

```
module ChromedriverWorkarounds

def fill_in(locator, options = {})
text = options[:with].to_s
if Capybara.current_driver == :selenium && text.include?('/')
# There is a nasty Bug in Chrome …

As the web is being used for more and more tasks, expectations rise. Not only should web pages offer rich interaction, they must be responsive in both size and interaction.

This imposes a paradoxon that needs to be solved by building performing applications. It's not enough any more to have your web site do crazy stuff, it is also required to do it crazy fast. This card is intended to give you an introduction to this emerging aspect of web development.

Read this introductory [performance study on Pinterest](http://www.smashingmagazine.com/…