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Updated: Raising JavaScript errors in Cucumber scenarios and how to silence them for particular scenarios

Added:

Cucumber output doesn't show JavaScript errors with the default progress formatter

Cucumber's "progress" formatter (many dots) do not show the JavaScript errors raised in the AfterStep above. The scenario will simply fail without an error message.

To see the error message, use the verbose formatter:

cucumber --debug

Or if you are using geordi:

geordi cucumber --debug
Repeats

An auto-mapper for ARIA labels and BEM classes in Cucumber selectors

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 …

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Rails: namespacing models with table_name_prefix instead of table_name

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…

Repeats

Using CSS transitions

CSS transitions are a simple animation framework that is built right into browsers. No need for Javascript here. They're supported by all browsers.

Basic usage

Transitions are used to animate the path between to property values. For example, to let the text color fade from red to green on hover, the following SASS is used (shorthand syntax):

.element
  color: red
  transition: color .1s
  
  &:hover
    color: green

This tells the browser "whenever the color of an .element changes…

Repeats

How to solve Selenium focus issues

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 ——————–…

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Cucumber pitfall: "Around" does not apply to your "Background" steps

Around will not happen until after a feature's Background has been processed. Use Before and After to avoid that.

Details

Consider this Cucumber feature file:

Feature: Something that needs to be tested

  Background:
    Given a user
      And I sign in        
    
  Scenario: Sign out
    When I sign out
    Then I should see "Signed out"
  
  Scenario: Something else
    # ...

Now, assume you have these step definitions:

Around do
  puts "** Around: before yield"    ...
Repeats

Dealing with I18n::InvalidPluralizationData errors

When localizing model attributes via I18n you may run into errors like this:

I18n::InvalidPluralizationData: translation data { ... } can not be used with :count => 1. key 'one' is missing.

They seem to appear out of the blue and the error message is more confusing than helpful.

TL;DR A model (e.g. Post) is lacking an attribute (e.g. thread) translation.
Fix it by adding a translation for that model's attribute (attributes.post.thread). The error message reveals the (wrongly) located I18n data (from attributes.thread)….

Repeats

Webpack(er): A primer

webpack is a very powerful asset bundler written in node.js to bundle (ES6) JavaScript modules, stylesheets, images, and other assets for consumption in browsers.

Webpacker is a wrapper around webpack that handles integration with Rails.

This is a short introduction.

Installation

If you haven't already, you need to install node.js and Yarn.

Then, put

```ruby
gem 'webpacker', '~> 4.x' # check if 4.x is still cu…

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Capybara/Selenium: evaluate_script might freeze your browser, use execute_script

In a nutshell: Do not use evaluate_script. Use execute_script instead!


Capybara gives you two different methods for executing Javascript:

page.evaluate_script("$('input').focus()")
page.execute_script("$('input').focus()")

While you can use both, the first line (with evaluate_script) might freeze your Firefox window for 10 seconds.

The reason is that evaluate_script will always return a result. The return value will be converted back to Ruby objects, which in case of complex objects (e.g. a jQuery collection) is *ver…

Repeats

Capybara: Quick checking for element presence (without retries or timeout)

Element finding is a central feature of Capybara. Since #find is normally used to get elements from the current page and interact with them, it's a good thing that some Capybara drivers (e.g. Selenium) will wait an amount of time until the expected element shows up. But if Capybara cannot #find it at all, you'll get an error.

if page.find('.that-element')
  # Do something
else
  # Never happens because #find raises
end

In order to simply check whether an element is present, without errors raised, you can use #has_css?. It wil…

Adding Jasmine JavaScript specs to a Webpack(er) project

The goal is to get Jasmine specs running in a Rails project using Webpacker, with the browser based test runner. Should be easily adaptable to a pure Webpack setup.

Image

Step 1: Install Jasmine

yarn add jasmine-core

Step 2: Add two separate packs

Since we do not want to mix Jasmine into our regular Javascript, we will create two additional packs. The first only contains Jasmine and the test runner. The second will contain our normal application code and the specs themselves.

We cannot…

Repeats

How to make RubyMine aware of Cucumber steps defined in gems

If your Ruby project includes a gem like Spreewald that comes with some external step definition, RubyMine does not know about them by default and will highlight the step as an undefined reference:

Image

To link these external step definitions to RubyMine, add the corresponding gems to your RubyMine-Settings:

  • Go to Settings (ctrl + alt + s)
  • Go to Languages and Frameworks
  • Go to Cucumber
  • There, add your gem (e.g "spreewald") via the little "+" from the b…
Repeats

Cucumber: Clear localStorage after each scenario

Capybara clears cookies before each scenario, but not other client-side data stores. If your app is using localStorage or sessionStorage, contents will bleed into the next scenario.

Use this hook to remove all site data after each scenario:

After do
  if Capybara.current_driver == :selenium && !Capybara.current_url.starts_with?('data:')
    page.execute_script <<-JAVASCRIPT
      localStorage.clear();
      sessionStorage.clear();
    JAVASCRIPT
  end
end

cucumber_factory: How to keep using Cucumber 2 Transforms in Cucumber 3

Cucumber up to version 2 had a neat feature called Step Argument Transforms which was dropped in favor of Cucumber 3 ParameterTypes. While I strongly encourage you to drop your legacy Transforms when upgrading to Cucumber 3, it might not always be possible due to their different design.
This is a guide on how to keep the exact same functionality of your old Transforms while writing them in the style of new `Paramet…

Repeats

Sass: Do not use comments between selector definitions

Sass lets you easily specify multiple selectors at once like this:

.some-block
  &.has-hover,
  &:hover
    outline: 1px solid red

This will add a red outline on either real hover or when the has-hover class is present. However, adding a comment will void the definition of that line:

.some-block
  &.has-hover, // From hoverable.js <-- DON'T
  &:hover
    outline: 1px solid red

… will simply drop the &.has-hover part.

Repeats

Heads up: Capybara 3's text matchers no longer squish whitespace by default

Until Capybara 2, node finders that accept a text option were able to find nodes based on rendered text, even if it spans over multiple elements in the HTML. Imagine a page that includes this HTML:

<div class='haystack'>
  Hi!
  <br>
  Try to match me.
</div>

Even though the text is separated by a <br> tag in the HTML, it is matched until Capybara 2 which used to "squish" text prior to the comparison.

```ruby
# Capyabara 1 or 2
page.find(…

Cucumber: Inspecting the Chrome download folder to test file downloads with Selenium

We already have some approaches on how to test file downloads withe selenium. Nonetheless here is another approach, which inspects the Chrome download folder. This way you do not need a separate logic on whether a file is served from a controller or a public path. The DownloadHelpers might also be re-used for reading e.g. a PDF file and checking its content.

Note: The step below will override a [spreewald step](https://gith…

Better compression for /boot partition

If you struggle with a /boot partition that is too small for updates, and you are too intimidated by the way to resize your /boot partition, there might be an easier fix:

It is possible to configure a better compression algorithm for the images in /boot. To do this, edit /etc/initramfs-tools/initramfs.conf and change the existing line to

COMPRESS=xz

Then rebuild the images using

sudo update-initramfs -u -k all

If you get an error during the last step, please immediately get help, because otherwise…

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