When you need to see the content of a page (i.e. not all the HTML but the relevant text body)

• you can do pp (html_content)
  • pp will format the html String human readable pretty printed
• where html_content can be replaced by one of the following commands:

Rails

body or response.body

Capybara:

• page.driver.html.content
• page.body

Webrat:

Nokogiri::HTML(response.body).content

The returned strings can be cleaned up by calling .gsub(/^\s*$/, '').squeeze("\n") on them.\
Although this may be useful for d...

There is a way to use multiple databases in Rails.
You may have asked yourself how you're able to keep your test databases clean, if you're running multiple databases with full read and write access at the same time. This is especially useful when migrating old/existing databases into a new(er) one.

Your database.yml may look like this:

default: &default
  adapter: postgresql
  encoding: unicode
  username: <%= ENV['DATABASE_USER'] %>
  host: <%= ENV['DATABASE...

tl;dr
You can use attribute? as shorthanded version of attribute.present?, except for numeric attributes and associations.

Technical Details

attribute? is generated for all attributes and not only for boolean attributes.

These methods are using #query_attribute under the hood. For more details you can see ActiveRecord::AttributeMethods::Query.

In most circumstances query_attribute is working like attribute.present?. If your attribute is responding to :zero? then you have to be aware that `query_attri...

You can use Unpoly's up.on with a named listener function and immediately unbind this event listener with { once: true }:

up.on('up:fragment:inserted', { once: true }, function () { ... })

In Unpoly 1 you can immediately unregister the listener with up.off:

up.on('up:fragment:inserted', function fragmentInsertedCallback() {
  up.off('up:fragment:inserted', fragmentInsertedCallback)
  // ... code for the callback function, which should run only once
})

Exam...

The gemspec for gems allows to add metadata to your gem, some of which have a special meaning and are helpful for users.
You can provide links to your Github bugtracker or changelog file that are then used on the rubygems page of your gem (in the sidebar, e.g. see gem page of consul).

Here are some keys that should be filled:

Gem::Specification.new do |s|
  s.name = 'my-gem'
  s.homepage = 'https://github.com/makandra/my-gem'

  s.metadata = {
    'source_code_uri' => s.homepage,
    'bug_tracker...

In Chrome DevTools you can use getEventListeners(object) to get a list of registered event listeners on the specified object.

You can also do this without the console, by selecting an element in the DOM inspector. In the element details, select the tab Event Listeners".

Example

const registry = getEventListeners(document)

registry['up-click']
// 0: { useCapture: false, passive: false, once: false, type: 'up:click', listener: ƒ }
// 1: { useCapture: false, passive: false, once: false, type: 'up:click', listener: ƒ }
//...

When you need information about a gem (like version(s) or install path(s)), you can use the gem binary from the command line, or the Gem API inside a ruby process at runtime.

gem binary (in a terminal)

You can get some information about a gem by running gem info <gem name> in your terminal.

Example:

$ gem info irb

*** LOCAL GEMS ***

irb (1.4.1, 1.3.5)
    Author: Keiju ISHITSUKA
    Homepage: https://github.com/ruby/irb
    Licenses: Ruby, BSD-2-Clause
    Installed at (1.4.1): /home/arne/.rbenv/versions/3.0.3/lib/ruby/g...

Merge requests are often rejected for similar reasons.

To avoid this, before you send a merge request, please confirm that your code ...

• has been reviewed by yourself beforehand
• fulfills every requirement defined as an acceptance criterion
• does not have any log or debugging statements like console.log(...), byebug etc.
• has green tests
• has tests...

When using threads, you must make your code thread-safe. This can be done by either locking (mutexes) all data shared between threads, or by only using immutable data structures. Ruby core classes like String or Array are not immutable.

There are several gems providing thread-safe collection classes in Ruby.

concurrent-ruby

The concurrent-ruby gem provides thread-safe versions of Array and Hash:

sa = Concurrent::Array.new # supports standard Array.new forms
sh = Co...

tl;dr: Use the URLSearchParams API to make your live easier if you want to get or manipulate query parameters (URL parameters).

URLSearchParams API

The URLSearchParams API is supported in all major browsers except IE 11.

It offers you a bunch of useful methods:

• URLSearchParams.append() - appends a query parameter
• URLSearchParams.delete() - deletes the specified query parameter
• URLSearchParams.get() - returns the value of the specified query parameter
• `URLSearchP...

An alternative to this technique is using VCR. VCR allows you to record and replay real HTTP responses, saving you the effort to stub out request/response cycles in close details. If your tests do require close inspection of requests and responses, Webmock is still the way.

WebMock is an alternative to FakeWeb when testing code that uses the network. You sh...

In Rails, we usually have a mailer setup like this:

class MyMailer < ActionMailer::Base

  def newsletter
    mail to: 'receiver@host.tld',
      from: 'sender@host.tld',
      subject: 'My mail'
  end

end

If you want to preview your mail in the browser, you can use the Action Mailer Preview. To inspect the mail directly in your email client, just create an .eml file and open it with your client:

mail = MyMailer.newsletter
Fil...

Due to the way we setup Jasmine tests in our projects, you may run into various errors when Jasmine boots.

Setting jasmineRequire on undefined

Jasmine 4 may fail with an error like this:

Uncaught TypeError: Cannot set properties of undefined (setting 'jasmineRequire')

This is due to issues in Jasmine's [environment detection](https://github.com/jasmine/jasmine/blob/502cb24bb89212917a3c943b593fd918ffc481cb/lib/jasmine-core/...

Sometimes you will need an input field which wraps content and grows in height as soon as content gets longer than the input fields width.
There is no way to get a "normal" string input field to wrap as desired, but there are other ways.

Here is one pretty easy solution to get what you want:

Step 1

Let your input became a text area with one row.

f.text_area(:name, rows: 1, autosize: '') 

Step 2

Include the autosize library in your project

yarn add autosize

And make your...

When working with ActiveType you will often find it useful to cast an ActiveRecord instance to its extended ActiveType::Record variant.

Starting with active_type 0.4.0 you can use ActiveType.cast for this:

class User < ActiveRecord::Base
  ...
end

class SignUp < ActiveType::Record[User]
  ...
end

user = User.find(1)
sign_up = ActiveType.cast(user, SignUp)
sign_up.is_a?(SignUp) # => true

This is basically like [ActiveRecord#becomes](http://apidock.com/rails/v4.2.1/ActiveRecord/...

When the order matters:

expect(array1).toEqual(array2)

Regardless of order:

expect(array1).toEqual(jasmine.arrayWithExactContents(array2))

Ignoring extra elements:

expect(array1).toEqual(jasmine.arrayContaining(array2))

Redis.current will be removed without replacement in redis-rb 5.0.
Version 4.6.0 adds deprecation warnings for Redis.current and Redis.current=:

`Redis.current=` is deprecated and will be removed in 5.0.

If your application still uses Redis.current, you can only fix it by no longer using it. Here is how.

Redis.new when you need it

You can easily instantiate a Redis client when you need it.

There is probably already a constant like REDIS_URL that you use to configure Sidekiq or similar. So just use that one.

``...

On Ruby 1.9+, standard ruby character classes like \w, \d will only match 7-Bit ASCII characters:

"foo" =~ /\w+/   # matches "foo"
"füü" =~ /\w+/   # matches "f", ü is not 7-Bit ASCII

There is a collection of character classes that will match unicode characters. From the documentation:

• /[[:alnum:]]/ Alphabetic and numeric character
• /[[:alpha:]]/ Alphabetic character
• /[[:blank:]]/ Space or tab
• /[[:cntrl:]]/ Control character
• /[[:digit:]]/ Digit
• /[[:graph:]]/ Non-blank character (excludes spaces...

Attaching files to a field that is handled by Carrierwave uploaders (or maybe any other attachment solution for Rails) in tests allows different approaches. Here is a short summary of the most common methods.

You might also be interested in this card if you see the following error in your test environment:

CarrierWave::FormNotMultipart:
You tried to assign a String or a Pathname to an uploader, for security reasons, this is not allowed.
If this is a file upload, please check that your upload form is multipart encoded.

Factor...

While we are used to run our JavaScript tests on a test page within our Browser, it's also possible to run them on the command line with NodeJS. I think that's actually the most common way to run JS tests.

Given a Vue project that uses Jest (via vue-cli-service) with the following package.json:

{
  "scripts": {
    "test": "vue-cli-service test:unit --testMatch='**/tests/**/*.test.js' --watch"
  },
}

This allows us to run J...

I recently was in a weird situation where my (Jest/CLI) tests were referencing a function that was no longer part of my code - I had just refactored it.

Apparently Jest has some kind of cache that caused the issue, running npx jest --clearCache solved it for me.

RSpec's let allows you to super into "outside" definitions, in parent contexts.

Example:

describe '#save' do
  subject { described_class.new(attributes) }
  let(:attributes) { title: 'Example', user: create(:user) }

  it 'saves' do
    expect(subject.save).to eq(true)
  end

  context 'when trying to set a disallowed title' do
    let(:attributes) { super().merge(title: 'Hello') } # <==

    it 'will not save' do
      expect(subject.save).to eq(false)
    end
  end
end

I suggest you don't make a habit of using this regula...