All browsers + IE9 know the CSS :empty selector. It lets you hide an element when it has no content.

For instance, you have a badge displaying the number of unread messages in a red bubble with white text:

.unread-messages-bubble {
  background-color: red;
  border-radius: 10px;
  padding: 10px;
  color: white;
}

To hide that bubble entirely when there are no new messages:

.unread-messages-bubble:empty {
  display: none;
}

Note that the element must be completely empty for `:empt…

In most projects I know, Cucumber test suite speed is not an issue. Of course, running 350 features takes its time, but still each test for itself is reasonably fast. There is nothing you can do to fundamentally speed up such a test (of course, you should be using parallel_tests).

However, in projects that go beyond clicking around in a web GUI and checking results, there might be various measures to speed up things. Katapult tests, for example, could be sped up more than 4 times by …

In RSpec you can tag examples or example groups with any tags you like simply by saying

describe ReportCreator, slow: true do
  # ..
end

describe ReportCreator do
  it 'generates reports', slow: true do
    # ...
  end
end

You can then only run examples with these tags.

rspec --tag slow
rspec -t slow

# Using the parallel_tests gem
rake "parallel:spec[,,--tag slow]"

Or you can run all examples except the ones with a certain tag:

```
rspec –tag ~slow # note the ~
rspec -t ~slow

Using the parallel_tests gem

rake "par…

If your application exports CSV, be advised that Excel and other spreadsheet applications treat certain cells (those starting with =, +, - or @ as formulas.

This is an issue if you output user input. Not only is it probably not what you want, it also poses a security risk. See the link for attack vectors.

Note that current Excel versions will warn the user when opening the file. At least for the code execution vulnerability, this warning seems adequate to me.

Solution

If possible, always **try to avoid CSV and output XLS(X) f…

You should override #respond_to_missing? instead of #respond_to? so your instances work with #method. Also see Marc's post.

Webpack opens the world of npm to Rails developers. It does not collide with the asset pipeline—however, it's kind of a parallel world and you'll probably be better off going for either Webpack or asset pipeline.

Prerequisites

1. Install a recent Node.js

   curl -sL https://deb.nodesource.com/setup_8.x | sudo -E bash -
   sudo apt-get install -y nodejs
   

2. Install Yarn

   curl -sS https://dl.yarnpkg.com/debian/pubk...
   

When you eagerly load an association list using the :include option, and at the same time have a :condition on an included table, two things happen:

1. Rails tries to load all involved records in a huge single query spanning multiple database tables.
2. The preloaded association list is filtered by the :condition, even though you only wanted to use the :condition to filter the containing model.

The second case's behavior is mostly unexpected, because pre-loaded associations usually don't care about the circumstances under which the…

Sometimes when working with VCR you still want to use webmock. Since VCR hooks into webmock and fails when an unknown request is happening, you have to turn it off in order to use webmock like you are used to. Here is how to do this in rspec.

RSpec.configure do |config|
  config.around do | example |
    if example.metadata[:turn_off_vcr]
      VCR.turn_off!
      example.run
      VCR.turn_on!
    else
      example.run
    end
  end
end

Requestb.in is a webservice that gives you a temporary URL you can use to test request. The page will automatically record and display the latest web request made to it.

We're usually running Ubuntu LTS versions. Sometimes newer hardware requires packages from more recent Ubuntu releases that only come with 6 months of support. If there is really no other way, it's possible to install packages from later Ubuntu releases

Caution: Pay really close attention to what you're doing. Depending on the package, this process may require upgrading a lot of dependencies, possibly breaking the system! You really should not do this unless you've carefully calculated the impact on your system

Preparation

First,…

Added new method with autocomplete="new-password".

In the DevTools settings, there's a "Shortcuts" section. Found these keyboard shortcuts there:

General

ESC

Toggle drawer

STRG + ~/`

Show console

Styles

PageUP/PageDOWN

Change number by 10

SHIFT + PageUP/PageDOWN

Change number by 100

Elements

H

Toggle "visibility:hidden!important" (useful when debugging page repaint times).

CTRL + hover above element in the DOM list

Don't show the yellow dimensions tooltip (useful when the tooltip covers just the area you need to see).

Drag & Drop

You can actually drag …

When you're using Sidekiq::Web to monitor the Sidekiq status AND have your session cookie configured to a wildcard domain like .example.com, you need to take an additional step to keep your cookies valid.

Issue

Sidekiq::Web is mounted into your Rails application and will use the Rails session cookie for protection from CSRF attacs. While it somehow figures out the cookie name, it does NOT respect cookie configuration like a custo…

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

When attempting to update RubyGems, depending on updates your previously performed, you might run into an error

ERROR:  While executing gem ... (TypeError)
can't convert nil into String

Fix this by running

gem uninstall rubygems-update -a -x

A common pattern in Ruby is to to require all files in a specific diretory, using something like

Dir.glob(Rails.root.join('lib/ext/**/*.rb')).each do |filename|
  require filename
end

However, this causes files to be required in an order determined by the file system. Since load order can be important, this may lead to different behavior on different machines which are hard to debug.

Simply add a .sort:

Dir.glob(Rails.root.join('lib/ext/**/*.rb')).sort.each do |filename|
  require filename
end

Added info about a small footgun with the current setting most of us are using. It's still the best option all around.

For most of us, current is the safest push behavior. However, it has a small side effect: When a branch with your local name does not exist on your remote, it automatically creates it on the remote.

While that is usually what you want, it does not setup tracking between your local and remote branches. That means git pull won't work, and Git won't notify you when your local and remote …