grosser/rspec-instafail

Gem to show failing specs instantly.
Unlike the --fail-fast option it doesn't abort abort on the first failure, but keeps running other examples after print out the failure.

I haven't tried it with parallel_tests.

Block formatting contexts

TL;DR Block formatting contexts establish an isolating container. float
and clear only apply to elements within such a container.

About

Block formatting contexts (BFCs) are important for the positioning and clearing
of floats. The rules for positioning and clearing of floats apply only to
things within the same block formatting context.

Floats do not affect the layout of things in other block formatting contexts,
and clear only clears past floats in the same block formatting context.

How to create a new block form...

Understanding z-index: it's about stacking contexts

The CSS property z-index is not as global as you might think. Actually, it is scoped to a so-called "stacking context". z-indexes only have meaning within their stacking context, while stacking contexts are treated as a single unit in their parent stacking context. This means indices like 99999 should never actually be needed.

Creating a new stacking context

In order to create a stacking context with the least possible side effects, use the isolation property on an...

Git: How to get a useful diff when renaming files

tldr; Use git diff -M or git diff --find-renames when you've moved a few files around.

Usage

$ git diff --help
  Options:
    -M[<n>], --find-renames[=<n>]
      Detect renames. If n is specified, it is a threshold on the similarity index
       (i.e. amount of addition/deletions compared to the file’s size). For example,
       -M90% means Git should consider a delete/add pair to be a rename if more than
       90% of the file hasn’t changed. Without a % sign, the number is to be read as
       a fraction, with a decimal point...

How to load an SQL dump from a migration

If you want to load an SQL dump from an ActiveRecord migration, you might find this to be harder than you thought. While you can call ActiveRecord::Base.connection.execute(sql) to execute arbitrary SQL commands, the MySQL connection is configured to only accept a single statement per query. If you try to feed it multiple statements, it will die with You have an error in your SQL syntax.

You can work around this by opening a second MySQL connection that does accept multiple statements per call.

Below is an example for a migration that l...

RSpec: Only stub a method when a particular argument is passed

To only stub a method call if a given argument is used, but use the default implementation for other arguments:

object.should_receive(:some_method).and_call_original
object.should_receive(:some_method).with('my argument').and_return('other value')

Requires rspec-mocks 2.13+.

Geordi 1.0 released

Geordi 1.0 features a command line application geordi, that holds most of Geordi's previous commands.

New features

  • command help and usage examples right within geordi (geordi help and geordi help <command>)

  • quick command access: type just the first few letters of a command, e.g. geordi rs or geordi dev[server]

  • command dependencies, e.g. geordi rspec invokes geordi bundle-install (which bundles only if needed)

  • no cluttered /usr/bin, but all commands in one handy tool

  • template for easily adding new...

How to set up database_cleaner for Rails with Cucumber and RSpec

Add gem 'database_cleaner' to your Gemfile. Then:

Cucumber & Rails 3+

# features/support/database_cleaner.rb

DatabaseCleaner.clean_with(:deletion) # clean once, now
DatabaseCleaner.strategy = :transaction
Cucumber::Rails::Database.javascript_strategy = :deletion

Cucumber & Rails 2

The latest available cucumber-rails for Rails 2 automatically uses database_cleaner when cucumber/rails/active_record is required -- but only if transactional fixtures are off. To have database_cleaner work correctly:

  1. Add the ...

How to circumvent Firefox's "Document expired" page in Selenium tests

When navigating back to a page that was received from a POST request, undesired side effects may happen. Therefore, modern browsers try to keep users from doing so, i.e. Firefox 24 displays an error page explaining what's wrong. If the user presses "Try Again", it shows an additional alert asking whether the user is certain.

Solution

If you need to circumvent this protection, e.g. to test that your application behaves correctly despite being misused, do this:

page.execute_script 'history.back()'
page.execute_script 'retryThis(this)...

How to view a file from another branch

Just run git show branch:file. Examples:

git show HEAD~:bin/command
git show origin/master:../lib/version.rb

ImageMagick: Cropping images

ImageMagick takes a string with several options when cropping an image. See the command line options for how to provide the expected image geometry for details.

Note that ImageMagick tends to preserve the original aspect ratio of the source image automatically.

Examples:

  • crop 200x200 means Maximum values of height and width given, aspect ratio preserved.
  • crop 200x200! means Width and height emphatically given, original aspect ratio ignored.

Jasmine 2 cheat sheet for RSpec lamers

In the tradition of our PostgreSQL cheat sheet for MySQL lamers, here is a cheat sheet for Jasmine when you're used to RSpec.

Note that Jasmine syntax has changed with Jasmine 2, so if you're using Jasmine 1.x you might instead want to use an older cheat sheet.

Expectations

# RSpec
expect(foo).to.eq("value")
expect(foo).to_not eq("value")

# Jasmine
expect(foo).toBe("value")
expect(...

Jasmine: Testing AJAX calls that manipulate the DOM

Here is a Javascript function reloadUsers() that fetches a HTML snippet from the server using AJAX and replaces the current .users container in the DOM:

window.reloadUsers = ->
  $.get('/users').then (html) ->
    $('.users').html(html)

Testing this simple function poses a number of challenges:

  • It only works if there is a <div class="users">...</div> container in the current DOM. Obviously the Jasmine spec runner has no such container.
  • The code requests /users and we want to prevent network interaction in our uni...

Jasmine: Reset the location when testing code that uses pushState / replaceState

When testing code that uses pushState / replaceState, your browser will appear to navigate away from http://localhost:3000/specs (or wherever you run your Jasmine tests). This is inconvenient, since reloading the document will no longer re-run the test suite.

To remedy this, copy the attached file to a place like spec/javascripts/helpers and #= require it from your tests. It will store the current location before every test and reset if afterwards (using location.replaceState).

How to upgrade Cucumber on Rails 3+

  1. Run bundle update cucumber capybara cucumber-rails to update to the newest versions.

  2. Backup your features/support/path.rb to be able to add your own paths again after the cucumber installation script in step 4.

  3. Backup your features/support/env.rb file to be able to reintegrate parts like your blueprints setup:

    ENV["RAILS_ENV"] ||= "cucumber"
    require File.expand_path(File.dirname(__FILE__) + '/../../config/environment')
    require 'spec/support/blueprints'
    
  4. Run `$ rails generate cucumber:install --capyba...

AngularJS: Binding to Perl-style getter/setters functions

Angular 1.3+ has an alternative getter/setter pattern: You can bind ng-model to an accessor function. This is a function that is either a getter (when it gets no arguments) or a setter (when it gets the new value as an argument):

$scope.name = function(newName) {
  return angular.isDefined(newName) ? (_name = newName) : _name;
}

You need to bind this function with ng-model and `ng-model-options="{ getterSette...

Getter and setter functions for JavaScript properties

JavaScript objects can have getter and setter functions that are called when a property is read from or written to.

For example, if you'd like an object that has a virtual person.fullName attribute that dynamically composes person.firstName and person.lastName:

var person = {

  firstName: 'Guybrush',

  lastName: 'Threepwood',

  get fullName() {
    return this.firstName + " " + this.lastName;
  },
  
  set fullName(name) {
    var parts = name.split(" ");
    this.firstName = parts[0];
    this.lastName = parts[1];
  }

};
`...

Testing focus/blur events with Cucumber

This is a problem when using Selenium with Firefox. We recommend using ChromeDriver for your Selenium tests.


This setup allows to test focus/blur events in Cucumber tests (using Selenium). For background information, see How to solve Selenium focus issues.

Cucumber step definition:

# This step is needed because in Selenium tests, blur events are not triggered
# when the browser has no focus.
When /^I unfocus the "(.*?)" field to trigger ja...

Taking screenshots in Capybara

Capybara-screenshot can automatically save screenshots and the HTML for failed Capybara tests in Cucumber, RSpec or Minitest.

Requires Capybara-Webkit, Selenium or poltergeist for making screenshots. Screenshots are saved into $APPLICATION_ROOT/tmp/capybara.

Manually saving a page

Additionally you can trigger the same behavior manually from the test using Capybara::Session#save_and_open_page and [...

Action Mailer Previews

Rails includes a way to see what an e-mail will look like.

Integration to RSpec

All you need to do is implement a preview-class in spec/mailers/previews/notifier_preview.rb:

class NotifierPreview < ActionMailer::Preview
  def welcome
    Notifier.welcome(User.first)
  end
end

And adapt the preview load path in your application.rb:

config.action_mailer.preview_path = "#{Rails.root}/spec/mailers/previews" # For Rails < 7.1
config.action_mailer.preview_paths << "#{Rails.root}/spec/mailers/previews" # For Rails >=...

The developer console can do more than you think!

You can do so much more than console.log(...)! See the attached link for a great breakdown of what the developer console can give you.

Some of my favorites:

console.log takes many arguments

E.g. console.log("Current string:", string, "Current number:", 12)

Your output can have hyperlinks to Javascript objects

E.g. console.log("Check out the current %o, it's great", location)

[Di...

Active Record and PostgreSQL — Ruby on Rails Guides

Rails guide that covers PostgreSQL-specific column types and usages for Active Record.

You should especially keep in mind the special datatypes that PostgreSQL offers. \
Types like json and array take away a lot of the pain that you had on MySQL projects.

Example use cases for array are tags or storing foreign keys (instead of a join model). You can even index them.

Reading an element's attributes with Capybara

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