calc() lets you mix CSS units. Ever wanted to give an element "the container's width minus 20px on each side"? Here you go:

width: calc(100% - (20px * 2));

When using Sass, you need to interpolate Sass expressions:

width: calc(100% - #{$margin})

Supported by all modern browsers and IE9+.

In JavaScript we often use Immediately Invoked Function Expessions (or IIFEs) to prevent local variables from bleeding into an outside scope:

(function() {
  var foo = "value"; // foo is scoped to this IIFE
})();

In Coffeescript an IIFE looks like this:

(->
  foo = "value" # foo is scoped to this IIFE
)()

There is also a shorthand syntax with do:

do ->
  foo = "value" # foo is scoped to this IIFE

You can also use do with arguments t...

In Rubocop you might notice the cop Style/CaseEquality for e.g. this example:

def foo(expected, actual)
  expected === actual
end

In case expected is a Regex, it suggests to change it to the following pattern:

def foo(expected, actual)
  expected.match?(actual)
end

In case expected is a Regex or a String, you need to keep ===. Otherwise the actual expression is always converted to a regular expression.

# For expected === actual
foo('Test(s)', 'Test(s)') #=> true

# For expected.match?(actual)
foo('Test(...

Here is a short summary of Cucumber hooks in Ruby taken from https://github.com/cucumber/cucumber-ruby. Note that the BeforeStep is currently not existing in the Ruby implementation of Cucumber.

Before hooks run before the first step of each scenario.

Before do |scenario|
  ...
end

After hooks run after the last step of each scenario, even when the step result is failed, undefined, pending or skipped.

...

For outputting a given String in HTML, you mostly want to replace line breaks with <br> or <p> tags.
You can use simple_format, but it has side effects like keeping some HTML.

If you only care about line breaks, you might be better off using a small, specialized helper method:

def format_linebreaks(text)
  safe_text = h(text)
  paragraphs = split_paragraphs(safe_text).map(&:html_safe)

  html = ''.html_safe
  paragraphs.each do |paragraph|
    html << content_tag(:p, paragraph)
  end

...

capybara_element['attribute_name'] allows accessing an element's attributes in Capybara.

A few examples:

find('#my_element')['class']
# => "first-class second-class"

find('#my_input')['placeholder']
# => "My placeholder value"

find('a#example-link')['href']
# => "http://example.com"

find('#my_element')['missing_attribute']
# => nil

In a project team for a bigger project people have several roles:

• Developer: at makandra
• Project lead: at makandra
• Project manager (PM): at makandra, external, or with the customer. In a smaller project this person is also the project lead.
• Product owner (PO): with the customer

Developer

• Development
• Take responsibility for their stories. This includes always gathering all necessary information from the project lead or the PM, communicate blockers, make sure stories are merged, deployed etc.
• Tell the project lead, if you'r...

Rails does not offer a "vanilla" way of negating an ActiveRecord scope. Here are two ways to do it yourself without too much effort.

Example:

class User
  scope :admins, -> { where(role: ['admin', 'superuser'] }
  # ...
end

Now what if we want a scope of users that are not admins? While you could declare a second scope like scope :non_admins, -> { where(role: ['guest', 'editor']) }, there are ways to use the opposite of the admins scope.

Option A: Subquery

You could just use a subquery. Doing that with scopes is easy...

Ubuntu 18.04 uses systemd to manage services.

See which Services are running

To get an overview which services are available and running / not running, you can use service --status-all:

>service --status-all
 [ + ]  acpid
 [ - ]  alsa-utils
 [ - ]  anacron
 [ + ]  apache-htcacheclean
 [ - ]  apache2
 [ + ]  apparmor
 [ + ]  apport
 [ + ]  avahi-daemon
 [ + ]  avahi-dnsconfd
 [ - ]  bluetooth
 [ - ]  bootmisc.sh
 [ - ]  brltty
...

+ means running, - means not running, ? means unknown

Manage Services

To temporaril...

Geordi provides a pretty neat way to generate beautiful commit messages according to your stories in Pivotal Tracker:

geordi commit

Geordi reads from a .geordi.yml file inside your repo and connects to Pivotal Tracker to list started and finished stories with their title. Choosing one of them generates a commit message including id and title from pivotal tracker. For example:

[#1234567] CRUD Users

Trouble shooting

If you encounter a bug like `40...

When accepting GIF images, you will also accept animated GIFs. Resizing them can be a time-consuming task and will block a Rails worker until the image is processed.

Save yourself that trouble, and simply tell ImageMagick to drop any frames but the first one.

Add the following to your uploader class:

process :remove_animation

private

def remove_animation
  if content_type == 'image/gif'
    manipulate! { |image| image.collapse! }
  end
end

You may also define that process for specific versions only (e....

We currently test most of our gems on Travis CI, but want to migrate those tests to Github Actions. This is a step-by-step guide on how to do this.

Note that this guide requires the gem to use gemika.

1. Go to a new "ci" branch:

   git checkout -b ci
   

2. Update gemika to version >= 0.5.0.
3. Have gemika generate a Github Actions workflow definition by running

   mkdir -p .github/workflows; bundle exec rake gemika:generate_github_actions_workflow > .github/workflows/test.yml
   

...